Demogorgon, Prince of Demons

Haste, Doublestrike, Trample, Reach, Hexproof, Menace. Demogorgon can block an additional creature.
{1}{r} Sacrifice a creature, Demogorgon gets +X/+X.
X is the creatures power.
Every time a player that doesn't control
Demogorgon attacks, flip, the winner gains control
of Demogorgon.
Demogorgon does 1 damage to it's controller,
every turn during the upkeep.