Video from NBC News
Yesterday morning in the Pilchuck River in Snohomish County, an 8-year-old boy swimming with his family suddenly found a 4 foot tall otter on his head, gnawing on his face. The boy's grandmother valiantly swooped in to save the boy, but got a nasty bite to the eye in the process. According to the boy's mother, "the otter stood on its hind legs and looked at them as if to say, 'Don't come in here'" and made a hissing noise at them.
The river has been closed as officials attempt to locate the rogue otter. In the meantime, the boy and his grandmother have received stiches and are recovering.
Moral of the story—if an otter stands on its hind legs, get the hell out of there before it tries to hold your hands (or your head).