Watt

Watt is Mario's sixth party member in Paper Mario.

On his way through Shy Guy's Toy Box, Mario encounters a monster called the Big Lantern Ghost. To defeat him, Bow had to smack the lamp to bring light into the room, giving Mario the ability to damage him. After his defeat, Mario finds a Lil' Sparky named Watt and releases her from the lantern. Overjoyed, Watt joins the party.

By pressing C-Down, Mario can light up dark places and find hidden blocks invisible to the naked eye (at least, until hit).