Gary, The Unspeakable's Vessel

Intimidate
At the beginning of each players upkeep,
that player creates a 0/1 red demon creature
token named "Red Demon" with "{r}, Sacrifice
this creature: Target demon you control gains
+1/+1 and your choice of Menace, Intimidate, or
Vigilance. If you control no demons, create a 0/0 colorless demon creature token named
'Gray Demon.' Any player may activate this
ability as a sorcery."