Octopus Umbra is a rare Enchantment — Aura card from Commander 2018 (C18), collector number 11. Current market price: $1.83, TCGplayer market prices via Scryfall.
Enchant creature Enchanted creature has base power and toughness 8/8 and has "Whenever this creature attacks, you may tap target creature with power 8 or less." Umbra armor (If enchanted creature would be destroyed, instead remove all damage from it and destroy this Aura.)