The Vacuum Helmet is a machine used by Dark Fawful in Mario and Luigi: Bowser's Inside Story. It appears to be the same helmet he used throughout Mario & Luigi: Superstar Saga. This helmet seems to be more intelligent as it has a life of it's own.
After Bowser inhales the helmet during his battle against Dark Fawful, the Mario Bros. will have to deal with it. Like in Superstar Saga, it can shoot orbs of energy. It can also suck up either the Bros. item Command Blocks or Special Attack Blocks.