I just learned a Bible story about bears. It’s in Kings 2: 22-23. Here’s how Skeptics Annotated Bible summarizes it:

God sends two bears to rip up 42 little children for making fun of Elisha’s bald head.

Here’s the passage:

2:23 And he went up from thence unto Bethel: and as he was going up by the way, there came forth little children out of the city, and mocked him, and said unto him, Go up, thou bald head; go up, thou bald head.
2:24 And he turned back, and looked on them, and cursed them in the name of the LORD. And there came forth two she bears out of the wood, and tare forty and two children of them.

[BTW, “tare” means “to pull apart or in pieces by force, especially so as to leave ragged or irregular edges.”]

I don’t remember hearing any sermons based on this passage.