Tenacity

 is a passive ability, which means it will be active as soon as the creature is in play.  For a list of all Cards with this ability, click here! 

Variations
usually only has a chance to activate, with rare exceptions. It will always activate when the creature receives fatal damage. The health after activation ranges from 1 to 4.

Strategy
The Mummy and Cardinal Sin are the two only creatures that will CERTAINLY revive (three times) after being killed, which makes them very powerful cards! Creatures Equipped with Weapons or Armor will retain them upon being revived.