Eel Umbra is a common Enchantment — Aura card from The List (PLST), collector number C18-89. Current market price: $0.27, TCGplayer market prices via Scryfall.
Flash (You may cast this spell any time you could cast an instant.) Enchant creature Enchanted creature gets +1/+1. Umbra armor (If enchanted creature would be destroyed, instead remove all damage from it and destroy this Aura.)