Enforcer Sentinel
From Halopedia, the Halo wiki
Summary
Enforcers, or Sentinel majors, are massive robotic automatons that serve to contain major Flood outbreaks. They are protected by an energy shield, but it only seems to protect the "front" on the machine. It is armed with rapid firing pulse beams similar to Needler fire, and mortar-like projectiles. It's mechanical grabbing arms can pick up entire vehicles if the driver is careless.
