Crab Umbra is a uncommon Enchantment — Aura card from Rise of the Eldrazi (ROE), collector number 58. Current market price: $0.38 (foil $6.68), TCGplayer market prices via Scryfall.
Enchant creature {2}{U}: Untap enchanted creature. Umbra armor (If enchanted creature would be destroyed, instead remove all damage from it and destroy this Aura.)