Brought by Douglas Fargo from Eureka, the M.A.R.A.s (Maintenance And Repair Automaton) are a series of spider-like maintenance and security robots, usually employed for unmanned space stations and large facilities such as Global Dynamics. They are able to shoot nets or fire, and have buzzsaws built in to their bodies.
Fargo brought the M.A.R.A.s with him to the Warehouse after he agreed to help upgrade the Warehouse computer. He was going to give them to Artie, but Artie wasn't impressed by them. They were used by Hugo One to secure the agents in the Warehouse, and deactivated entirely thereafter.