Rudolph was feeling real sad / but then a miner made him feel refreshed
They got together with some freak toys / The Bumble only wants your flesh
The Bumble seems to be remembered by most people as a puffy, lovable goofball, but he tried to eat everyone in that movie at some point. It's heavily implied that he kidnapped Rudolph's parents and girlfriend Clarice, but I could be wrong about that. If so, it was a real faux pas when he picked up Rudolph's girlfriend by her neck and tried to put her in his mouth. Party foul, am I right?
When Rudolph shows up to politely ask him not to put his girlfriend in his mouth, the Bumble goes after Rudolph instead. This is a calculated move. It shows that the Bumble has some sort of guiding intelligence. He's not just an animal trying to eat. If he were, Clarice would be a pile of Bumble turds. The Bumble then fights with Rudolph, hitting him over the head with a stalactite and laughing maniacally when Rudolph passes out. This proves that he has a sense of humor and enjoys slapstick -- redeeming qualities, but nothing that necessarily outweighs his other, more homicidal qualities.
When the movie ends, it's only been a few hours since the Bumble pummeled Rudolph, but Yukon Cornelius, emperor of misguided optimism, declares the beast "reformed." The Bumble ends the movie happily placing the star on Santa's Christmas tree. Aww, the rampaging animal is nice now. I guess it just goes to show you that even vicious cryptozoological terrors can have hearts of gold. Please. If that movie had gone on for two minutes longer, it would've ended with an elf buffet.