Krark, the Thumbless is a rare Legendary Creature — Goblin Wizard card from Commander Legends (CMR), collector number 189. Current market price: $1.68 (foil $2.12), TCGplayer market prices via Scryfall.
Whenever you cast an instant or sorcery spell, flip a coin. If you lose the flip, return that spell to its owner's hand. If you win the flip, copy that spell, and you may choose new targets for the copy. Partner (You can have two commanders if both have partner.)