Leonardo's Technique is a rare Sorcery card from Teenage Mutant Ninja Turtles (TMT), collector number 18. Current market price: $0.32 (foil $0.39), TCGplayer market prices via Scryfall.
Sneak {1}{W} (You may cast this spell for {1}{W} if you also return an unblocked attacker you control to hand during the declare blockers step.) Return one or two target creature cards each with mana value 3 or less from your graveyard to the battlefield.