The Wing Cap is an item found in Super Mario 64 and Super Mario 64 DS. When wearing a Wing Cap, Mario has the ability to fly. To obtain the item, Mario must find a red ! Block and hit it. A Wing Cap will then pop out of the ! Block.
It is of some interest to note that when Mario obtains a Wing Cap, the music that begins to play is the same tune as the music that plays when Mario acquires an invinciblity Star in the original Super Mario Bros..