Builder Mario is the form Mario, Luigi, Toad or Toadette take in Super Mario Maker 2. The Mario troupe can use this form after picking up a Super Hammer, a power-up found exclusively in the Super Mario 3D World style.
It adds a tool belt and a hardhat, and, in Mario and Luigi's case, changes their attire to yellow shirts and their trademark colored overalls. It grants Mario troupe the ability to swing a large hammer to slam the environment and enemies alike.
Unlike Hammer Mario, where the hammers are arched projectiles, Builder Mario uses them as a melee weapon, similar to the hammer attacks in the Paper Mario series and the Mario & Luigi series. Builder Mario can also create a maximum of five Builder Boxes at a time to be used as platforms.
In Mario & Luigi: Superstar Saga + Bowser's Minions, Builder Mario's helmet can be seen inside the Mario Bros.' House.
In Super Mario Odyssey, a cap and outfit based on Builder Mario's attire (named the Builder Helmet and the Builder Outfit respectively) can be purchased from the Crazy Cap store in the Metro Kingdom using regional coins.
In Super Smash Bros. Ultimate, Builder Mario appears as an alternate costume of Mario. Additionally, he appears as a fighter spirit that can be purchased from the Vault Shop.