FENRIS Mech

FENRIS Mechs are anti-infantry robots that resemble varren. Like the similar LOKI and YMIR mech models, these machines have white exterior armor and have parts the emit red light. FENRIS Mechs appear to attack by directly charging at the player, and their heads discharge electricity which may be how damage is inflicted.

Mass Effect 2
Commander Shepard encounters FENRIS mechs and other mech models frequently in combat.

Source: Game Trailers Droid Battle Gameplay