Professor E. Gadd wearing the gown, from Mario & Luigi: Superstar Saga
The Ghost Suit


The Ghost Suit was an invention created by Professor Elvin Gadd some time during the events of Mario and Luigi: Superstar Saga. It is a pale blue jacket that turns the wearer into an only partially-visible "ghost". E Gadd introduced the invention in Starbeans Café, where Luigi got so scared that he sucked up Gadd with the Poltergust 3000.