Silkguard is a rare Instant card from Secrets of Strixhaven Commander (SOC), collector number 286. Current market price: $0.77, TCGplayer market prices via Scryfall.
Put a +1/+1 counter on each of up to X target creatures you control. Auras, Equipment, and modified creatures you control gain hexproof until end of turn. (Equipment, Auras you control, and counters are modifications.)