Bill Cipher, Isosceles Demon

Flying, indestructible, deathtouch
{t}: take control of target tapped creature until it
untaps. Control only one creature at a time.
{3}: tap target creature. This creature does not
untap during any untap steps.
{3}: create a black 2/2 horror creature token.
When Bill Cipher, Isosceles Demon attacks, if he's
blocked, he gets +1/+1 until his power is equal to
the creature blocking it.
"Let's make a deal..."