"A favourite of Mario's in his younger days, the Hammer enraptures any character that grabs it and sends them into a clobbering frenzy!" —Super Smash Bros.'s instruction manual.

The Hammer (ハンマー, Hammer) is a close-range item that appears in all Super Smash Bros. games. Upon being grabbed by any player, it sends them into a unique state that inflicts significant damage and knockback.

The hammer comes from the arcade game Donkey Kong. In Donkey Kong, when Mario obtains the hammer, he is unable to stop swinging until the hammer disappears. He also is unable to jump or climb ladders while swinging the hammer. The hammer can be used to destroy barrels that are being rolled down towards Mario, and can be used against other enemies. Contrary to its depiction in the Super Smash Bros. series, the Hammer's head cannot fall off in the game, nor can it otherwise malfunction.

The hammer has since been absorbed into iconography of the Mario universe, with Mario himself using hammers on several occasions. Notable instances of Mario using a hammer is the Wrecking Crew series, Paper Mario series, Mario & Luigi series, several mini-games in the Mario Party series, and as an occasional item in the Mario Kart series.

Upon picking up the Hammer, characters enter a unique state for eight seconds; they will constantly swing the hammer back and forth, and will be unable to midair jump, use any other attacks, or defend. The Hammer also cannot be manually dropped unless the user has been sent into a state of tumbling. The Hammer deals about 22% per hit, and it also deals extremely high vertical knockback, potentially KOing opponents at low percentages; the effects of the Hammer are even more formidable in Super Smash Bros., where the Hammer instead does 30% damage with even more knockback. The Hammer can also "chain" into itself, doing 60% and likely KOing the opponent. The Hammer disappears after seven seconds.

The Hammer, however, limits the user's options, and particularly careful hitbox placement by other characters can potentially interrupt the wielder. Counters are especially powerful against Hammers since most of them deal more damage for any attack they counter. As the wielder of the hammer cannot use special moves or midair jump, sending an opponent off a ledge while they swing the Hammer can effectively KO them unless they can somehow drop the Hammer. In Super Smash Bros. Brawl and Super Smash Bros. 4, the Hammer also operates on a "timer"; if a character wielding the Hammer is constantly hit so that they cannot swing the item, the timer will still count down, potentially getting rid of the Hammer before they can properly use it.

The Hammer is also an item in Smash Tour: when its trophy is selected, the user starts the battle wielding a Hammer.

an item that, once grabbed, makes you swing non-stop. It's a powerful attack item that does terrific damage and sends opponents sailing. Once in a great while, the hammer's head will fall off, leaving you nothing but the handle. Of course, you can't tell whether the head is securely fastened just by looking. Hammerheads that fall off can be picked up and thrown as weapons.

Mario's favorite hammer in his youth is already here. immerse yourself in the adventure and connection Mario has with this hammer (since he helped him save Pauline and defeat the old Donkey Kong) Hello everyone, I am again. Excuse me, this time I did not come with an Skin but with a very powerful weapon that does not deserve to be forgotten. I will return with more skins, I have thinking about climbing several more and then giving myself some rest to fix the other skins that are wrong. And update some things ... However, enjoy this weapon and beat your enemies with her.