Antilon anti-personnel mine
From Halopedia, the Halo wiki
Antlion Anti-Personnel Mines[1], are used by the UNSC and many other military services, being used as an anti-infantry role, as their explosive splashes, yield more damage to unshielded targets. The mines will kill any unarmored opponent but will most likely deplete an armored opponents' shields so the attacker can move in for an easy kill. They are capable of both proximity and manual detonation. They can be used in Campaign and Multiplayer. Also, they will explode automatically after a time if no one steps on it.
