When I was still an early teen or pre-teen, my mom did a stint as a school counselor for a school for behavior-challenged teens. Juvenile Delinquents, basically.
I don't really know all the details, but I remember they had records of things like drugs, skipping school, emotional issues, whatever. The kids who couldn't hack the regular schools and acted out, or had issues regular schools couldn't hack.
I've been in contact with the kids a couple of times - at least once a field trip (I remember one kid burning wings off flies, and wanting to kill the fish I'd caught), and once at the school, and at their graduation, too. Probably a few more times, since I can still remember many of their names and faces distinctively.
Anyway, once I was at the school for a short time - maybe on my summer break, or a sick day? I had my usual reading material - D&D stuff. They were interested, and in short order I was DMing A2 Secret of the Slaver's Stockade for them. I gave them the pre-gens but I think they renamed them.
They didn't make it far. Part of that is because that dungeon is a deathtrap - here, assault a fortress! - and the other is because they had no interest in exploring. Or treasure. Or anything beyond combat.
The immediately set to killing each other. The details are vague - I remember being annoyed and disappointed - but it ended when one girl (maybe the one girl who played) found out that fireball had this big blast radius that would encompass the whole party. She threw it, it blew up, and they all died. Maybe even her guy, too.
I just remember looking at the map, describing the gatehouse, and they didn't even make it past that. The intra-party stealing and killing just started right up. I may have tossed the ankheg in - I remember the ankheg coming up.
They seemed to have fun, and I never did run game for them again. Probably for the better. But it's still such a distinct memory. Especially B~ throwing the fireball to kill them all.
I can look back on that and criticize them or me, but it doesn't matter. They enjoyed themselves, and I have a memory for life from that. It's not a good way to run a long campaign, though - starting out by killing each other off. Still, it wasn't the first time I played with people who played it "wrong" but got the fun they wanted out of it.