School Shooting Funny Bone

Alright, listen up, buttercup. The joke is funny because it's about school shootings, which ain't funny at all! But the punchline brings it back to a "funny bone," see? You probably don't know much about bones, but you should at least know that the "funny bone" is a nerve in your elbow that hurts real bad when you hit it, but not "real bad" like what happens in the joke!