Vardzi, Undying Temptress

Deathtouch
Whenever a player casts a creature spell, put a +1/+1 counter on Vardzi, Undying Temptress. Then, if it has seven or more +1/+1 counters on it, destroy all creatures.
Creature spells cost {2} less to cast.
"The trick is not to hide the curse, but to exaggerate the blessing."