Mario's Glove

Mario's Gloves are a part of Mario's clothing. He wears them in every appearance, except for some older games (e.g. Wrecking Crew or certain Game & Watch titles), and in appearances where he is a baby. In Luigi's Mansion, Mario loses one of his gloves inside the mansion, forcing Luigi to search for it. It is eventually found in the Projection Room after clearing the Cinema Ghosts haunting it. In the 3DS version's Hidden Mansion, however, it is instead found in the Courtyard after clearing all of the Ceiling Surprises and Purple Bombers in the area.

After giving it to Madame Clairvoya she says: "Wh-what is this? If it isn't Mario's Glove! Ah-hah! Still damp with the sweat of the living!"

Luigi's Mansion (Nintendo 3DS)

 * In-game description: "The white gloves Mario wears. They're a little damp from sweat..."

Trivia

 * Even though Mario "lost" his glove in Luigi's Mansion, he is still shown wearing them both while in his painting. The same applies to his hat and shoe.
 * As stated by Shigeru Miyamoto, Mario's design was originally given white gloves to make his movements easier to spot when he jumped. Mario's line in The Super Mario Bros. Movie about the gloves being a means to stand out, while in context being about the gloves as a visual gimmick for their plumbing company, was likely written as a nod to this point of origin.