Gleeful Arsonist is a rare Creature — Human Wizard card from Duskmourn: House of Horror Commander (DSC), collector number 56. Current market price: $5.63, TCGplayer market prices via Scryfall.
Whenever an opponent casts a noncreature spell, this creature deals damage equal to its power to that player. Undying (When this creature dies, if it had no +1/+1 counters on it, return it to the battlefield under its owner's control with a +1/+1 counter on it.)