Cap

A cap is the type of hats seen in the Mario franchise. Mario using the Wing Cap

Some caps have special abilities like turning Mario and friends into living metal, an invisible being, and into each other. The Wing Cap is a regular cap that has wings on it allowing the user to fly for a short time. the special uses of these caps have been used mostly in Super Mario 64 and it's sequel Super Mario 64 DS.

Cap Wearers
These are the characters who have been seen usually wearing a cap.

Mario

Luigi

Baby Mario

Baby Luigi

Wario

Waluigi

Shadow Mario

Cosmic Mario

Trivia
JumpMan (The orignal name for Mario) was not supposed to have a hat, instead he was supposed to have hair. But the quality and graphics back then made it impossible for his hair to flow, so they gave him his famous red cap.