It's a cat in a box. No, seriously. Like this:

　　 　　∧ ∧＿__　　　
　　 ／（*ﾟーﾟ）　／＼　　
　／|￣Ｕ　Ｕ￣|＼／　　　　
　  |　　しぃ  |／　　
　 　 ￣￣￣￣　　　　　　

Oh wait, I don't have any good pictures. Sorry for wasting your time.

There's also a song, but I don't know it. I'll make something up:

Shii ni ni, shii ni ni, wa-aaave, goodbye.

(I'll fix this someday)