Praetorian

Praetorians  are terrifying cybernetic constructs used by the  Collectors  in  Mass Effect 2 and in multiplayer mode in Mass Effect 3. These bio-mechanical tanks are produced by fusing thirty  Husks  into a single form that largely resembles the Collector General. They are heavily armoured and generate biotic barriers, making them difficult to destroy. In combat, they hover above the battlefield and blast enemies with powerful particle beams. They can also fight on the ground by using their legs as weapons and unleashing biotic shockwaves to destroy all surrounding enemies.

In Mass Effect 3, Praetorians appear more angular and streamlined. They largely operate in the same fashion as in ME2, but in this game they gain a substantial boost in defensive and offensive power when possessed by Harbinger.