Idea from Skorpion, posted in the Nyan Cat Vehicle Suggestion thread. (Couldn't quote it because it was locked.)
"A gun that looks like Nyan Cat.
That shoots rainbows.
The shells that it ejects out of it's arse will be poptarts.
The shooting sound will be the nyan song.
The impact kills enemies with one hit.
Gogogo.
Infact, Ima make a topic bout dis." - Skorpion
To be honest it would be pretty cool.