Celestial Serpent

Celestial Serpent enters the battlefield with seven +1/+1 counters on it.
Remove a counter: Prevent the next 7 damage that would be dealt to Celestial Serpent.
Add a charge counter to Celestial Serpent: It gains "At the beginning of your upkeep, you may exchange your life total with the number of charge counters on Celestial Serpent."