Boar Umbra

Umbra armor's effect is applied no matter why the enchanted creature would be destroyed: because it's been dealt lethal damage, or because it's being affected by an effect that says to "destroy" it (such as Breathe Your Last). In either case, all damage is removed from the creature and the Aura is destroyed instead.

Umbra armor's effect is mandatory. If the enchanted creature would be destroyed, you must remove all damage from it (if it has any) and destroy the Aura that has umbra armor instead.

If a creature enchanted with an Aura that has umbra armor would be destroyed by multiple state-based actions at the same time (most likely because a creature with deathtouch has dealt damage to that creature greater than or equal to its toughness), umbra armor's effect will replace all of them and save the creature.