My thing is a Fugazi sticker, which humorously declares "This is not a Fugazi sticker". It doesn't create a good sound when my box is shaken (unlike Marceline's coin), but I do like it. In fact, I'm tempted to stick it on something. But if I do that, I'll have partially destroyed my item, and therefore my box. So I'm not going to stick it on something.
Simon Minter, Oxford