The OMACs (Omni Mind And Community) are a race of robots that can control human hosts. They were originally designed to monitor metahuman activity. However, they have since gone rogue following some reprogramming by the Justice League's adversary Maxwell Lord. They are controlled by Brother Eye.
Official LEGO Description
OMAC™ (Observational Metahuman Activity Construct) is a member of a super-powered cybernetic army controlled by Brother Eye™, an all-seeing satellite orbiting the Earth. Infected with a high-tech virus, each OMAC is encased in nearly invulnerable armor that grants them incredible super-strength, super-speed, flight and the ability to fire destructive energy blasts. As one of Brother Eye’s soldiers, each OMAC is sent on missions wherever needed around the world and is virtually unstoppable.