The Witch of Izalith

Annihilator X, where X is the number of
witch you control.
{6}{r}, {t}: Sacrifice The Witch of Izalith: it deals
X damage to each creature, where X is the
number of lands you control that can produce {r}. Then you may put onto the battlefield
The Bed of Chaos, a red token X/X, where X
is the number of creatures destroyed this way.