Collective Combustion

Target player sacrifices X creatures. If X is 5 or
more, target player sacrifices all creatures instead.
For each creature sacrificed this way, it's
controller can deal 2 damage to any target.
Overload {x}{r}{r}{w}, Pay 5 Life (You may cast this
spell for its overload cost. If you do, change its text
by replacing all instances of "target" with "each.")
The worth of a soul? Of two? Of many? Not my
concern. It is for you to experience.