Ugh. Definitely D&D's most infamous campaign: Tomb of Horrors. If you've not heard of it, imagine Ikaruga or any other bullet hell game. Then make it medieval with magic and traps everywhere.
I had a character, level fifteen or so (out of twenty) get the flesh melted from his skull along with his helmet for LOOKING AROUND A CORNER.
I had a character, level fifteen or so (out of twenty) get the flesh melted from his skull along with his helmet for LOOKING AROUND A CORNER.