Legacy of Blood Revenge

Until end of turn, whenever you cast a creature
spell, destroy target creature with converted
mana cost X or less and all creatures opponents
control with the same name as that creature. Its
controller sacrifices a non-creature permanent for
each creature destroyed this way.
Whenever a creature you control entering or
leaving the battlefield this turn causes an ability
to trigger, it triggers X additional times.
This spell costs {1} less to cast for each creature
card in your graveyard.