(If you're looking for the boss, go here: Tape)
The Tape is an item found in Paper Mario. Apparently, Koopa Koot lended this item to Goompa a long time ago, and now wants it back. One of Koopa Koot's favors is for Mario to bring the Tape back from Goompa's house. If Mario goes to Goompa in Goomba Village and asks, Goompa will give it back. It is unknown what is on this tape.
This Tape is comparable to Toadstool's ??? in Super Mario RPG: Legend of the Seven Stars, the Box in Paper Mario: The Thousand-Year Door and the You-Know-What in Super Paper Mario. All four of these items show or contain mysterious things that the hero cannot know about.