Voidshadow Sentry

Fabricate 7 (When this creature enters the battlefield, put seven +1/+1 counters on it or create seven 1/1 colorless Servo artifact creature tokens.)
Flying, menace
Revolt - When Voidshadow Sentry enters the battlefield, if a permanent you controlled left the battlefield this turn, target player loses 4 life and you gain 4 life.