Community's done zombies, space, multiple timelines, 1984 parodies, claymation, and soon, rumor has it, vampires. So, why not magic?
"SPECIAL TOPICS IN ALCHEMY"
Pierce, an amateur stage magician, gets excited when the long-defunct Magic Department is revived for a "Special Topics" course, but there aren't enough students registered. He asks the study group to register, and, thinking it's going to be a blow-off class on Harry Potter, they agree.
They find the classroom in the dungeon, a smoky room full of test tubes, cauldrons, and strange powders. The instructor, Professor Bumbleboor (played by Michael Grambon), believes he is a real, magical, wizard who has unlocked the secrets of alchemy: specifically, the Philosopher's Stone, which grants the user special powers.
The class' first assignment is to make one of their own. So, what would each study group member do with their stone?
When Professor Bumbleboor mentions that the stone has the power to revive dead plants, Britta feels compelled to announce that she's going to use her stone to save the rainforest. No one believes she'll actually do it, which only strengthens her resolve. But when she discovers how many vaccines she has to get to go to the Amazon, she backs out of the trip. Unfortunately, since she can't admit this without losing face, she spends a week hiding around campus trying not to be seen, including having to bribe Magnitude with her flashing breasts (Pop, pop).
Shirley starts turning everything in sight into gold. She says she's going to use the money to finally get her business off the ground and spend some money on her kids, but as time goes on, the "gifts" she's buying become more and more of a stretch. Do the boys really need a treehouse, a pet lamb, and monogramed everything? But as long as the gold keeps flowin', Shirley keeps spendin'.
Pierce, who has been recently feeling the effects of aging, would instantly ask for eternal youth. Turns out, young Pierce was a megafox -- taking a break from appearing in our naughty dreams, special guest star Michael Trucco. Despite remaining as sexist and crotchety as ever, the women of Greendale fall for him instantly. Even Dean Pelton won't give Jeff the time of day anymore -- leading to an all-out, rugged-good-looks vs. rugged-good-looks battle over who has the rights to be Greendale's most eligible bachelor.
Troy and Abed
Upon discovering that alchemy can be used to create clones, Abed and Troy get to work creating their own clone army with the hopes of having more free time to do awesome things. Unfortunately, all of the clones are created with all of Troy and Abed's memories, including of creating clones. Now no one -- not even Troy and Abed themselves, know which two are the originals. They declare a battle royale in the Dreamatorium, but it's so epic and so awesome that all the Troys and all the Abeds decide to coexist.
Annie's stone gives her the ability to turn rocks into diamonds! Wheeee! Starburns offers to trade some of the bounty of his stone, which turns water into liquor. And many tumblers later, Annie and Starburns make the drunken decision to get married, seeing as how he already has a top hat and she already has a diamond. So they set off on an epic adventure to find a jeweler who can set her comically huge rock -- easier said than done!
Please. Jeff doesn't believe in magic. But when the evidence grows too strong to ignore, he begins to fear the stone's magic, which surpasses even his own powers of persuasion. He appoints himself head of the Defense Against the Dark Arts and tries to rein in the powers of darkness that have seized Greendale.
Of course, then the DEA bursts in, acting on a tip that Bumbleboor has been smoking an insane amount of weed -- which is, incidentally, responsible for the smoke in the classroom and the class' visions.
As they sober up, the clone army disappears, Annie comes to her senses and slaps Starburns, and, saddest of all, Pierce returns to normal. While showrunner Dan Harmon is probably looking for ways to write Chevy Chase off the show, if Joel McHale and Michael Trucco appear on the same screen for too long, the universe would probably implode.
So farewell, Hot Pierce, we'll miss you.