Ingenious Leonin is a uncommon Creature — Cat Soldier card from Foundations Jumpstart (J25), collector number 211. Current market price: $0.32, TCGplayer market prices via Scryfall.
{3}{W}: Put a +1/+1 counter on another target attacking creature you control. If that creature is a Cat, it gains first strike until end of turn. (It deals combat damage before creatures without first strike.)