In Harry Potter and The Goblet of Fire, Barty Crouch Jr. kidnaps and then impersonates Alastor “Mad Eye” Moody through the use of Polyjuice Potion. The magic juice allows the drinker to take on the form of someone else. It can only be used between humans. A human cannot take the form of an animal. This Mad Eye Moody t-shirt advertises Alastor’s Polyjuice Potion. It is also what allowed Harry Potter, Hermione Granger and Ron Weasley to investigate the Chamber of Secrets during their second year at Hogwarts. This Polyjuice Potion shirt won’t enable you to impersonate your friends, but you will look cool wearing it nonetheless. We don’t advise you to try to pull out pieces of your friends' hair either.