Servoversoul

Servos you control get +X/+X where X
is the number of Servos you control.
Sacrifice 10 Servos you control: Until end
of turn, Servoversoul becomes a X/X Legendary
Artifact Creature - Construct with Lifelink,
Trample, Hexproof, Indestructible, and
"When this creature attacks, destroy X creatures
opponents control and put X 1/1 Colorless Servo
creature tokens into play under your control"
where X is the number of Servos you control.