Hyena Umbra is a common Enchantment — Aura card from The List (PLST), collector number UMA-21. Current market price: $0.36, TCGplayer market prices via Scryfall.
Enchant creature Enchanted creature gets +1/+1 and has first strike. Umbra armor (If enchanted creature would be destroyed, instead remove all damage from it and destroy this Aura.)