This may not quite be a stupid death, but it had some entertaining notes that I wanted to share.
--For this Grey Elven Wizard named Seeker who cruised through the early game, an uncontrolled teleport on the Casino level summoned many Casino guards to stop his ‘theft.’ While killing guards in self-defense, alignment dropped to NL, making him a fallen champion. After killing the guards, killing the shopkeeper, and looting the Casino, the C fallen champion of Order quickly descended to the Darkforge shortcut
--Having no Lightning Ball but having found Executor in the Casino, the wizard cleared Darkforge in melee. In order to alleviate the cursed-and-doomed status of a fallen champion, he quickly carried 80K gold to the most convenient available chaotic altar…..in the Fire Temple. Then proceeded to the deeper CoC, gaining proficiency in Axes
--Seeker reached level 40 and the Mana temple without ever having seen a spellbook of Acid Ball, Ice Ball, or Lightning Ball. The mixed tension room on the Mana Temple level included one Balor, killed with demon slaying ammo.
--Clearing out the summoners and stooges in the Mana Temple was relatively easy. After that, though…Four swings of Executor produced four misses of Nuurag-Vaarn, so the wizard decided to replicate the Balor-execution. Seeker lured Nuurag-Vaarn into the hallway, and began to ply his longbow and stack of 16 blessed arrows of humanoid slaying. Unfortunately, fully 14 of the 16 arrows missed, and Seeker was blasted into oblivion.

Perhaps a lesson: Seeker used two wishes on Find Weakness and Archery, on the assumption that a spellbook of acid ball would show up eventually. Maybe that was a flawed assumption!