Noxious Eruption

Rift (This costs {2} less to cast for each spell that has been cast this turn that shares a color with it).
For each tapped land target player controls, Obliterate (To obliterate, put a ruin counter on target land. Lands with ruin counters on them can produce only {c}. Its controller may pay 2 life to remove the counter as a sorcery)