1) noun - A group of bears that have been set aflame
2) adj./adv. phrase - a slang expression to add emphasis, excitement, or intensity to a sentence. Usually used to describe something hot, flaming, burning etc.
3) noun - a slang expression meaning to rebel. Usually yelled in a battle cry fashion to express the fact to everyone you are going against the man
(Got its third meaning in response to the censorship to have bears on fire)