Skyknight Squire is a rare Creature — Cat Scout card from Foundations (FDN), collector number 448. Current market price: $0.57 (foil $0.78), TCGplayer market prices via Scryfall.
Whenever another creature you control enters, put a +1/+1 counter on this creature. As long as this creature has three or more +1/+1 counters on it, it has flying and is a Knight in addition to its other types.