Ever wonder what a polar bear would dress up as for Hallowe'en?
Maybe a ghost.
He could be a wizard, like Saruman or something, if he put on a long wig.
Or a yeti, but he would have to walk around all day up on his hind legs.
With some dye he could go as a black bear.
Ooh- I know- with a little shimmery makeup applied in the right places he could go as the aurora borealis! That would be cool.