Ultra Hammer

The Ultra Hammer is one of the most powerful weapons in Mario's possession. The item first appeared in Super Mario RPG: Legend of the Seven Stars. In the game, the Ultra Hammer is seemingly Mario's most powerful weapon. However, a hidden item, known as the Lazy Shell, is actually Mario's most powerful weapon.

In Paper Mario and Paper Mario: The Thousand-Year Door, the Ultra Hammer is Mario's strongest hammer. In battle, an uncharged Ultra Hammer attack deals six damage to a defenseless enemy (while Mario's normal Hammer only delivers two damage).

In Mario & Luigi: Superstar Saga, the Ultra Hammer is the third and last Hammer upgrade Mario and Luigi receive. With it, they can break black rocks on the field. The Hammers are not any stronger in battle, though.

Trivia
In Super Smash Bros. Brawl, Golden Hammers resemble the Ultra Hammer.