A Shrunken Head
Shrunken heads were a very popular practice back in the day. Depending on the culture, it was used to for less-than-ideal intentions. A true shrunken head is rare to come by, though. The process is very difficult to get right!
Amy Winehouse's "Poo"
Yes, this is a real thing on display at a museum. Is the poo itself real? Apparently, Viktor Wynd says so. Most people say that it's not. Honestly, it's just a weird thing to have on display and a weird thing to lie about in general. People can get pretty weird!