Marine Unmanned Aerial Vehicle Squadron 4 (VMU-4) is an unmanned aerial vehicle (UAV) squadron in the United States Marine Corps that operates the RQ-21 Blackjack. It is the fourth UAV squadron in the Marine Corps and the first in the reserve component. The squadron, nicknamed the "Evil Eyes", entered the force structure on 1 July 2010, when Marine Observation Squadron 4 (VMO-4) was reactivated and redesignated VMU-4.