The Great Old One

Indestructible
When you cast this creature from the command
zone, sacrafice it and place a dark devotion counter
on target creature you don't control.
When a creature with a dark devotion counter on
it dies, create a token copy of The Great Old One
under your control, except it's not Legendary and
has "When this creature is the target of a spell or ability, sacrafice it. It can't be regenerated."
{7}{u}{b}: Move this creature from the command
zone to your hand.