I’ve been looking at a pattern of clues in the six Harry Potter books, namely a series of interweaving and overlapping references to Transfiguration magic, secret passages/the Marauder’s Map, and trophies. Putting them all together, I believe they may be clues that the Helga Hufflepuff’s golden cup is in the trophy room at Hogwarts but Transfigured into TM Riddle’s Medal for Magical Merit (note: I am not referring to the Award for Special Services to the School, but a separate award that was only mentioned once). I’m not 100% certain this is the correct conclusion, but there is a pattern, and a good case can be made for the theory.
The clues in the breadcrumb trail supporting this theory are numbered below; my commentary for each clue is asterisked (*), and my summary is at the end:
1. Harry’s first Transfiguration textbook was A beginner’s Guide to Transfiguration by Emeric Switch (PS5).
*Transfiguration is magic that changes one object into something else (such as Transfiguring a match into a needle or using a Switching Spell to change a dragon’s teeth into wine gums). The HP Lexicon lists the many uses and types of Transfiguration used in the HP books (http://www.hp-lexicon.org/magic/transfiguration.html).
*Emeric is a variation of the name Almeric. Almeric comes from the Old Germanic name Amaliricus, which is derived from "amal" (work) and "ric" (power, rule, ruler, kingdom).
*Switch means to exchange one thing for another.
2. Helga Hufflepuff is described in the Sorting Hat’s songs in Philosopher’s Stone and Goblet of Fire as prizing hard work.
Those patient Hufflepuffs are true
And unafraid of toil; (PS7)
For Hufflepuff, hard workers were
Most worthy of admission;(GF12)
*The name Hufflepuff suggests toil and exertion (huffing and puffing), and she valued "hard workers" and students "unafraid of toil." These call to mind the name Emeric (derived from "amal" (work) and "ric" (power, rule, etc.)).
3. In the first description of Professor Binn’s History of Magic class, "Binns droned on and on while they scribbled down names and dates, and got Emeric the Evil and Uric the Oddball mixed up." (PS8)
*Emeric Switch and Emeric the Evil are not the same person, but the name Emeric is used only twice in the books (this class reference and the textbook author) and appear fairly close together (PS5 and PS8). Moreover, in the second usage of the name, information pertaining to an evil character (Emeric the Evil) is switched with information pertaining to a good one (Uric the Oddball), which is an allusion to Transfiguration magic (switching, exchanging, inversion, etc.).
4. The first mention of the Hogwart’s trophy room comes in PS9 when Draco Malfoy challenged Harry to a wizard’s duel at midnight in the trophy room, chosen because it was never locked. On the same page, Fred and George mention that Lee Jordan thought he’d found a new secret passageway out of the school; the twins thought it might be the one behind the statue of Gregory the Smarmy that they found during their first week at Hogwarts. (PS9)
*The Wizarding duel proposed by Draco was itself a set-up for a deceitful switch since Draco’s intention was to tip-off Filch so that Filch would find Harry and Ron in the trophy room after curfew.
*This is the first mention of secret passages out of Hogwarts. When Rowling mentions secret passageways or the Marauder’s Map, a reference to the trophy room is often very close to it.
*The trophy room is never locked, which means anyone would be able to access it at any time and no one regards the objects in it as very important. It’s a perfect place to hide something of great value that has been disguised to look like an object of low value.
5. Hermione, not yet friends with Harry and Ron, followed them out of the Gryffindor common room the night of the wizard’s duel, hissing like a goose, and trying to dissuade them from going to the trophy room by saying that if caught, they would lose all the points she had gained from McGonagall for knowing about switching spells ("Don’t you care about Gryffindor, do you only care about yourselves, I don’t want Slytherin to win the house cup, and you’ll lose all the points I got from Professor McGonagall for knowing all about Switching Spells.") (PS9)
*Hermione makes a direct reference to Switching Spells and the Transfiguration teacher during a conversation about the trophy room.
6. We got our first look at the trophy room when Harry, Ron, Hermione, and Neville entered the room: "They sped up a staircase to the third floor and tiptoed toward the trophy room. Malfoy and Crabbe weren’t there yet. The crystal trophy cases glimmered where the moonlight caught them. Cups, shields, plates, and statues winked silver and gold in the darkness." (PS9)
*The trophy room is crowded with various objects from Hogwarts’s long history, so hiding an additional trophy at Hogwarts would be easy.
*The trophy room is on the third floor (the same floor as the statue of the one-eyed, humpbacked witch that we learn in PA opens to reveal the secret passageway leading to the cellar of Honeydukes).
7. Lucius Malfoy picked up Ginny Weasley’s A Beginner’s Guide to Transfiguration textbook when he met her in Flourish and Blotts and then dropped it back into her cauldron. (CS 4) Ginny later said she found what turned out to be Riddle’s Diary Horcrux in one of her textbooks, so Lucius had placed the diary inside Ginny’s Transfiguration textbook.
*This is a clear Transfiguration magic/Horcrux association.
8. The next mention of the trophy room is in CS7, when Ron is sent to polish the silver in the trophy room for detention: "Fourteen times he made me buff up that Quidditch Cup before he was satisfied. And then I had another slug attack all over a Special Award for Services to the School." (CS7)
*Although Ron’s assignment was to polish silver items, it’s apparent from the next passage that the Special Award for Service to the School is gold. This may be a flint or an indication that Ron had to polish Riddle’s award because he accidentally vomited slugs on the gold shield even though he hadn’t been assigned to polish it.
9. While walking past a classroom, Harry could hear Professor McGonagall, the Transfiguration teacher, shouting at a student who had turned his friend into a badger. Later, Professor McGonagall appeared in the hallway with the student, who still had black-and-white-striped hair. (CS11)
*Helga Hufflepuff's animal emblem is a badger, so this passage clearly links Transfiguration magic with a badger, the same emblem that is on the gold Hufflepuff cup.
10. After Harry and Ron found the Riddle diary in Myrtle’s bathroom, Ron recalled that T. M. Riddle was the name of the student who got the Special Award for Services to the School that he had polished during detention. Harry, Ron, and Hermione returned to the trophy room to see if they could find more information about T. M. Riddle: "Riddle’s burnished gold shield was tucked away in a corner cabinet. It didn’t carry details of why it had been given to him [snip]. However, they did find Riddle’s name on an old Medal for Magical Merit, and on a list of old Head Boys." (CS13)
*This is the only mention of Riddle’s Medal for Magic Merit in all six books. Interestingly, it’s only mentioned once and only in a cluster of related objects. The heavy gold locket at 12 Grimmauld Place that many believe is the missing Slytherin locket Horcrux was similarly mentioned only once and only in a cluster of related objects.
11. A third mention of Riddle’s Award came when Harry began to write in the diary and Diarymort wrote back about the opening of the Chamber of Secrets 50 years earlier: "They gave me a nice, shiny engraved trophy for my trouble and warned me to keep my mouth shut." (CS13)
*The Award for Special Services to the School was given to Riddle for framing Hagrid as the culprit who opened the Chamber of Secrets, causing Moaning Myrtle’s death. It had taken Riddle five years to find the Chamber of Secrets, so it had galled Riddle to give Hagrid "credit" for being the Heir of Slytherin. The Diary Horcrux, in its capacity as a weapon, was Riddle’s means of insuring that one day he would receive credit for being the Heir of Slytherin who opened the Chamber of Secrets.
12. Diarymort told Harry that it had taken Tom Riddle five whole years to find the entrance to the Chamber of Secrets. (CS17)
*Since Riddle searched the castle for five whole years before locating the entrance to the Chamber of Secrets, he must have learned about one or more secret passages from Hogwarts to Hogsmeade. The Weasley twins found one of the passageways during their first week at Hogwarts.
13. Ron and Harry received Special Awards for Services to the School at the end of CS for their work in rescuing Ginny and destroying Diarymort (CS18), and those shields would have been placed in the trophy room with Riddle’s.
*This is a nice little twist since Harry received the same award as Tom Riddle for the same action: discovering the identity of the person who opened the Chamber 50 years earlier and killed Moaning Myrtle. More importantly, Harry’s actions revealed the true innocence of Hagrid and the true falseness of Tom Riddle in the Chamber episode, thereby switching the judgments of 50 years earlier.
14. The next mention of the trophy room is in Prisoner of Azkaban when the Weasley twins gave the Marauder’s Map to Harry in a third floor classroom near the statue of the one-eyed, humpbacked witch. Scanning the map, Harry noted that "Peeves the Poltergeist was currently bouncing around the trophy room." The map showed a series of passages leading from the school into various locations in Hogsmeade: "Right into Hogsmeade," said Fred, tracing one of them with his finger. "There are seven in all. Now Filch knows about these four"—he pointed them all out—"but we’re sure we’re the only ones who know about these. Don’t bother with the one behind the mirror on the fourth floor. We used it until last winter, but it’s caved in—completely blocked. And we don’t recon anyone’s ever used this one, because the Whomping Willow’s planted right over the entrance. But this one here, this one leads right into the cellar of Honeydukes. We’ve used it loads of times. And as you might’ve noticed, the entrance is right outside this room, through that one-eyed old crone’s hump." (PA10)
*This is the first of two references to Peeves bouncing around in the trophy room; this first one precedes a description of the school’s secret passageways.
*It should be noted that some secret passages are easier to find and open than others. The passageway behind the statue of Gregory the Smarmy that the twins found during their first week at Hogwarts is apparently easy to find and access. But Harry would not have known how to use the secret passageway through the one-eyed witch statue if the map hadn’t revealed the directions to him: "What did he have to do? He pulled out the map again and saw, to his astonishment, that a new ink figure had appeared upon it, labeled Harry Potter. This new figure was standing, about halfway down the third-floor corridor. Harry watched carefully. His little ink self appeared to be tapping the witch with his minute wand. Harry quickly took out his real wand and tapped the statue. Nothing happened. He looked back at the map. The tiniest speech bubble had appeared next to his figure. The word inside said, "Dissendium". (PA10) Moreover, after Snape caught Harry looking suspicious near the statue, Harry saw him "running one of his hands over the one-eyed witch’s head, examining it closely," trying to figure out what was special about it (PA14)
*Filch, as caretaker, should know about all secret passageways but apparently does not. Filch’s ignorance of the passageway near the one-eye, humpbacked witch near the trophy room is confirmed in PA when Harry noticed that although numerous security trolls had been hired to guard all entrances into the castle, the statue of the one-eyed, humpbacked witch was unguarded and unblocked (PA14). It’s an open question whether other members of the Hogwarts staff are aware of this passageway.
*The fourth floor passageway behind a mirror caved in during the winter of CS, but was clear during PS. It’s possible that Voldemort told Quirrell to use this secret passageway to sneak in the troll into Hogwarts on Halloween in PS. The text is unclear in pinpointing what floor the troll was on when it entered the girl’s bathroom where Hermione was crying, but the HP Lexicon has worked out that it was probably on the fourth floor. There was never any explanation given in PS to explain how Quirrell sneaked a 12-foot, rank-smelling mountain troll onto the fourth floor just before the Halloween Feast began (when teachers and students would have filled the corridors and stairways).
*Gunhilda of Gorsemoor (1556 - 1639), Famous Wizard Card #37
One-eyed, hump-backed witch who is known for developing a cure for Dragon Pox.
This is not in the books, but it’s possibly a clue since Rowling writes all the copy for the Famous Wizard cards. There can’t be too many one-eyed, humpbacked witches commemorated with a statue at Hogwarts or Famous Wizard card, so it’s a good guess that the statue leading to the secret passage to Honeydukes is Grunhilda of Gorsemoor. She was born around 500 years after Slytherin left the school, so Tom Riddle might not have found the secret passageway to Honeydukes in his search for the opening of the Chamber of Secrets if he concentrated on areas old enough to be around before Slytherin left the school and/or if he only recited various incantations in Parseltongue, knowing that only the Heir of Slytherin could open the Chamber of Secrets and expecting that his ability to speak Parseltongue would be the key to opening it. Also, the password through Gunhilda is "Dissendium," not a word that would immediately come to mind to open a passageway through a statue up on the castle’s third floor. I’m taking these clues as hints that Voldemort is unaware of the secret passageway through the one-eyed, humpbacked witch even if he knows of other secret passageways.
15. The next time the trophy room is mentioned is in Goblet of Fire when Harry, fresh from his after-curfew bath with the Golden Egg in the prefects’ bathroom, checked the Marauder’s Map, once again saw Peeves bouncing around in the trophy room, and also saw Bartemius Crouch in Snape’s office. (GF25) Determined to follow Crouch, Harry ran down the stairs in his invisibility cloak and became trapped when his leg fell through a trick step. The map went flying and the egg bounced down the stairs, then opened up and let out a screeching noise. Following the noise, Filch appeared shortly followed by Snape; both in their nightshirts. Snape mentioned that on the way he noticed his office door open, torches lit inside, and a cupboard door open; he then mentioned he was missing potions ingredients and hinted that students attempting illicit mixtures were guilty (that should have reminded us that Hermione stole from Snape’s private cupboard to make Polyjuice in CS). Fake Moody appeared next, saw Harry under the Invisibility Cloak with his magical eye, took the map before Snape could get it, and got rid of Filch and Snape. Harry mentioned seeing Barty Crouch on the map in Snape’s office; Fake Moody scanned the map at this, and, "He looked suddenly alarmed." Moody claimed not to see Barty Crouch on the map even though Harry had seen him only minutes before, and Crouch couldn’t have gotten far enough away to fall off the map. Fake Moody asked Harry if he could borrow the map, and then sent Harry off to bed.
*This is the second of two references to Peeves bouncing around in the trophy room; this second one preceded a series of clues showing the reader that Professor Moody is not who he appears to be. As we all know, Fake Moody was Death Eater Barty Crouch, Jr. transformed to appear as Order of the Phoenix member Alastor Moody (another good-evil inversion). So once again, a mention of the trophy room was closely linked to a transformation in which one thing (Crouch) was magically altered to appear as another thing (Moody).
16. In Order of the Phoenix, Peeves is linked to Transfiguration. When Harry wanted to used Umbridge’s fireplace to check on Sirius, Hermione suggested diverting Umbridge by telling her that Peeves was up to something: "I'll do it," said Ron at once. "I'll tell her Peeves is smashing up the Transfiguration department or something, it's miles from her office. Come to think of it, I could probably persuade Peeves to do it if I met him on the way." (OP32)
*Peeves has been linked to the trophy room in a passage introducing the secret passageways, in a passage introducing key clues that reveal Fake Moody as a transformed importer, and here he is linked to the Transfiguration classroom (associated with switching, inversions, false identities, physical transformations).
17. In Half-blood Prince we learned about Horcruxes, Voldemort’s collection of distinguished "trophies" used to house parts of his soul. We saw the Hufflepuff cup in HBP20 in the pensieve memory of Riddle’s visit to Hepzibah Smith: it was a small gold cup engraved with a badger with two finely wrought handles.
*Transfiguration magic in its many versions is frequently described in the six Harry Potter books to date. A small gold cup could easily be Transfigured to look like any number of objects; however, when we see the Transfiguration of objects, the starting and ending objects often have associations of various types such as similarity of phonics (beetles into buttons), of name (guinea fowl into guinea pigs), of shape (matchsticks into needles), of size (mice into snuffboxes), of a key physical attribute (hedgehogs into pincushions), etc., but sometimes the objects have no apparent connection other than size (desk into pig, rock into terrier, man’s corpse into a bone). The small gold cup could easily be Transfigured into a number of small gold objects of any appearance.
18. In HBP20, Dumbledore recounted to Harry that Voldemort had gone to work for Borgin and Burkes after leaving Hogwarts: :He reached the seventh year of his schooling with, as you might have expected, top grades in every examination he had taken. All around him, his classmates were deciding which jobs they were to pursue once they had left Hogwarts. Nearly everybody expected spectacular things from Tom Riddle, prefect, Head Boy, winner of the Award for Special Services to the School."
*What is curious about this passage is that Dumbledore did not mention the Medal for Magical Merit that we saw in the trophy room in CS. While it could be that the Medal for Magical Merit was given to Riddle for his top examination grades, no such award has been mentioned in connection with Bill or Percy Weasley, each of whom had earned twelve OWLS (the most you can receive) and had been prefect and Head Boy. We certainly would have heard about a Medal for Magical Merit if Percy had received it, so it appears not to be a commonly awarded honor. And logic tells us it's not a common award since we do know that becoming Head Boy is an exceptional honor, yet Head Boys are only remembered by their names on a list, not by individual objects like badges or medals. So if it’s not a commonly-awarded honor, then all the more reason for Dumbledore to have remembered Tom Riddle’s receiving it. But Dumbledore didn’t mention this apparently rarely-awarded medal, so we have to consider that it wasn’t awarded to Tom Riddle at all, but rather created by him and Dumbledore was unaware of its existence.
19. We’ve learned over the course of the books that Dumbledore never really trusted Riddle and that Riddle never tried to charm Dumbledore as he had the other teachers. We learned in HBP that the admissions of unethical magic made by Riddle to Dumbledore in the orphanage were the original source of this mutual distrust and that Slughorn had advised Riddle not to mention Horcruxes to Dumbledore because he was particularly fierce about the subject and had maintained (if not imposed) a school-wide ban on the subject.
*Voldemort, I suspect, would take keen pleasure in planting a Transfigured Horcrux under Dumbledore’s nose at Hogwarts since 1) Riddle regretted giving Dumbledore information revealing his ability to speak Parseltongue and his predilection for cruelty, secrecy, and control and probably resented Dumbledore’s knowing so much about him, 2) Dumbledore was even more distrustful of Riddle after Moaning Myrtle’s death and kept an annoyingly close eye on Riddle after Hagrid was expelled, 3) Dumbledore was particularly fierce on the subject of Horcruxes whereas Riddle was particularly keen on it, and 4) Dumbledore was the Transfiguration master who had taught the subject to Riddle in the first place.
20. Dumbledore made various unsuccessful attempts to bypass the poison in the sea cave. He told Harry, "This potion cannot be penetrated by hand, Vanished, parted, scooped up, or siphoned away, nor can it be Transfigured, Charmed, or otherwise made to change its nature." (HBP26)
*Although Dumbledore was unsuccessful in transforming the poison, it’s key that he mentioned trying to Transfigure it into something else or otherwise to make it change its nature. It’s also important to note that he was working with a protection covering a Horcrux, not the Horcrux itself.
It’s easy to see the breadcrumb trail of interweaving and overlapping references to Transfiguration magic, secret passages/Marauder’s Map, and the trophy room running through the Harry Potter books. In the context of Book 7’s hunt for the remaining Horcruxes, this trail of set-ups is arguably pointing to a Transfigured Horcrux in the trophy room at Hogwarts.
Many of us suspect the Slytherin Locket Horcrux is the heavy gold locket that nobody could open at 12 Grimmauld Place. The only other known Horcrux object likely to be hidden in the Hogwarts trophy room is the Hufflepuff cup. And the cup, seeming to be a tiny loving cup, fits an associational pattern seen throughout the books in Transfiguration magic, so it’s the best fit for a Transfigured Horcrux hidden in the trophy room. The association between the names Emeric Switch and Helga Hufflepuff (both with connotations to work, Switch pointing to Transfiguration), are clues. The accidental Transfiguration of a student into a badger (Hufflepuff's mascot) also point to Hufflepuff's Cup being the object in question.
The object we’ve seen most likely to be the Transfigured cup is Tom Riddle’s Medal for Magical Merit. I had at first questioned it because Voldemort hates his Muggle name, but if for no other reason than plot practicality, the trio need to be able to identify it as belonging to Riddle/Voldemort, and since Tom Riddle’s name is on the Award for Special Services and the Head Boy list, the name would raise no suspicions to anyone looking around the trophy room. However, I won’t be surprised if the medal is examined closely and found to have a tiny badger on it similar to the tiny snake on the bathroom tap marking the opening to the Chamber of Secrets. Moreover, the fact that his name is on the Horcruxed Medal fits a pattern whereby Voldemort leaves evidence in Horcrux locations of what he has done. See the essay explaining the green potion in the cave: http://felicitys-mind.livejournal.com/3530.html
Why would Voldemort hide a Horcrux in the trophy room at Hogwarts? Horcruxes are trophies as we learned in HBP, and the trophy room, a room never locked that no one ever goes into, would not be suspected as a place where Voldemort had hidden part of his soul. Hogwarts is the most well-protected building in Britain, and Lord Voldemort had happy memories there as student Tom Riddle. And for practical purposes, Harry and the trio need to find at least some of the remaining Horcruxes that are relatively unprotected (relative to the powerfully cursed Peverell ring and locket). There would be no need to protect a Transfigured Horcrux that looked like hundreds of other objects in a little-used room, and since the trophies in the room are occasionally handled for polishing, the Horcrux couldn’t be cursed in the manner of the opal necklace or Peverell ring.
Lastly, I agree with others that a confrontation between Harry and Voldemort will happen at Hogwarts. It’s the place both love best in the world and is a place Voldemort would very much want to control, especially if he has a Horcrux or two hidden there. With Dumbledore gone, the way is open to him. Hogwarts will need to be the setting for a showdown for reasons related to plot practicality; in the battle at the Ministry of Magic at the end of OP, Dumbledore was able to Apparate into the atrium in time to save Harry from Voldemort’s curse, Dumbledore was able to Disapparate before Voldemort’s Avada Kedavra curse reached him, and Voldemort was able to Disappate out of the building when he sensed a lost cause. So Harry and Voldemort will need to face off in a place in which Apparation and Disapparation are not possible, and the two places we've seen that fit the bill are Hogwarts and the Department of Mysteries (where I think the final battle will take place because of the Veil in the Death Room and the Love Room containing the most powerful magic known in the Potterverse).
I believe the reason why clues linking Transfiguration magic and trophies are interwoven with references to the Marauder’s Map and secret passageways running from Hogwarts to Hogsmeade is that Harry will need to get into and out of the castle without Voldemort's knowledge, and he won't be able to use Apparation or conventional entrances. Not only does the map show us how Tom Riddle could have slipped the Transfigured Horcrux into Hogwarts without being noticed, but it hints that Voldemort probably does not know about all the secret passageways. If he knew about the fourth floor passageway through the mirror and used it to help Quirrell get the troll into the school in PS, then he’ll find out it’s now blocked. He probably does not know about the passageway from the one-eyed, humpbacked witch to Honeydukes for the reasons argued above, and that passageway leads to the third floor, down the hall from the trophy room.
One last thought about the passageways. Who knows about them among the people who will be at Hogwarts in Book 7, and how many do they know about? Harry, Ron, and Hermione (and anyone they share the map with) will also know about all the secret passageways. The twins know about them all because they had memorized the map before handing it to Harry. The biggest potential surprise could come from the two remaining Marauders: Peter (Wormtail) Pettigrew and Remus Lupin since both created the Marauder’s Map, so both know about all the secret passageways. Will this be connected to the way Wormtail repays his life debt to Harry? I have a hunch it will.