Swarmbots are built from the Robobrain torso frame and is capable of hovering due to the Mister Handy thruster mounted below them. They are frequently encountered in groups, as their name implies.
Largely armed with automatic weapons, they are quickly capable of tearing down an unaware player character. However, they are quite quick and will frequently move into melee range while enjoying ranged support from the automated forces they travel alongside.
The Mechanist's automatrons are cobbled together from a wide variety of components taken from five different robot models. Swarmbots usually consist of a Robobrain torso and an Assaultron head mounted on a Mr. Handy's hover-chassis. Their arms come as varied as their armaments, which cover almost the entire spectrum of what an automatron can carry for ranged combat.
The Cybermech variant relies on two arm-mounted laser weapons, to eliminate targets from a distance. The shell of the Cybermech swarmbot is made of rusty metal scrap painted yellow and its legs look very much like a Mister Handy's arms. This type of swarmbot is very rare and only spawns when the Sole Survivor has reached level 45.
The Quantum swarmbot is the most powerful and rare swarmbot in the entire game. The body is also made up of a variety of scrap metals painted yellow and an Assaultron head. It also has two arm-mounted Tesla rifles and the body is covered by a Tesla-field. On defeat, its power source will overload, causing a large explosion. The Quantum swarmbot only first spawns when the player character has reached beyond level 60.