Demomorgon, Eater Of Souls

Demomorgon, Eater Of Souls can't be countered.
When Demomorgon, Eater Of Souls enters the battlefield, you choose a creature each opponent controls, then exile the rest.
Whenever a creature an opponent controls dies,
that player loses 3 life.
{t}, {x}{b}: Each player returns up to {x} creatures
from his or her graveyard to the battlefield tapped.
When Demomorgon, Eater Of Souls dies, exile
all creatures, then return creatures from exile to
the battlefield tapped.