Cavern Dweller

If an opponent was dealt damage last turn Cavern Dweller costs {3} less to cast. If an opponent lost seven or more life last turn Cavern Dweller costs {6} less to cast.
Whenever an opponent is dealt damage put a +1/+1 counter on Cavern Dweller. Whenever an opponent is dealt seven or more damage, put a +1/+1 counter on each creature you control.