Stache

A mustache (also called moustache, and 'Stache in the Mario & Luigi series) is a form of facial hair common in male adults such as Mario, Luigi, Wario, and Waluigi. Mario (and thus the palette swap Luigi) was originally given his mustache to clarify the borders of his nose, while Wario and Waluigi's mustaches are just parodies of Mario and Luigi's and are therefore angular and unrealistic. Many other characters, like the false Millennium Star, Eldstar, one of the Delfino Police, and Toadsworth, also have mustaches. Additionally, mustaches can be a source of pride, as demonstrated by the various mustachioed bosses of Super Mario 64. In Super Mario 64 DS, they often insulted Mario, Luigi, and Wario for their supposedly inferior mustaches. For example, Goomboss set such store by mustaches that he mistook Luigi for Mario (based on the mustache similarities). Big Bob-omb seemed to regard mustaches as a source and sign of power. Chief Chilly, after defeated, will even blame it on having a poor mustache.

In the Mario & Luigi RPG series, "'Stache" acts as a statistic in the game, similar to Luck in other RPGs. It gives Mario and Luigi better chances at getting a "Lucky" (Critical) hit in battle, and gives discounts to items bought at shops. Baby Mario and Baby Luigi also get these stats in Mario & Luigi: Partners in Time, though they don't have mustaches. Bowser's equivalent in Mario & Luigi: Bowser's Inside Story is "Horn."

According to Fracktail in Super Paper Mario, Mario has a "level 5 mustache". The Yellow Apple found in The Overthere makes Princess Peach grow a mustache similar to Mario's.