Harsh Mentor is a rare Creature — Human Cleric card from Amonkhet (AKH), collector number 135. Current market price: $0.36 (foil $2.63), TCGplayer market prices via Scryfall.
Whenever an opponent activates an ability of an artifact, creature, or land on the battlefield, if it isn't a mana ability, this creature deals 2 damage to that player.