Master Sword

The Master Sword is a recurring weapon originating from the The Legend of Zelda franchise. It is the legendary sword capable of repelling and sealing evil ones who will try to steal and use the Triforce for their designs. Waiting to be pulled out of its pedestal, only a hero who has proven their worth can use it, which is attributed to the sword choosing and accepting the wielder as its master.

In crossovers with the Mario franchise, the Master Sword appears along with its wielder, Link, in games such as the Super Smash Bros. titles and Mario Kart 8.

Super Mario-Kun
While the Master Sword itself does not appear in Super Mario-Kun, a sword that parodies the Master Sword called the Kinoko Sword (alongside an upgraded version called the Master Kinoko Sword) appears instead.

Super Smash Bros. series
Link wields the Master Sword in all Super Smash Bros. games, along with Toon Link in Super Smash Bros. Brawl and up. They use the sword in a multitude of moves, mostly those that are standard attacks. As of Super Smash Bros. Ultimate, Link's Master Sword is able to fire Sword Beams when Link uses his forward smash at 0%.

In addition, the Master Sword appears in Super Smash Bros. Melee as a trophy, which can be obtained when it appears at random in one of the game's single-player modes.

Mario Kart 8 / Mario Kart 8 Deluxe
In Mario Kart 8 and Mario Kart 8 Deluxe, the Master Sword rests in a pedestal at a crossroad inside the Hyrule Castle in Hyrule Circuit. It acts as a Spin Boost Pillar, but is initially inaccessible. On the track leading to the sword, there are three spin boost crystals that, when activated, cause the sword to rise up from the pedestal along with a Dash Panel ramp that allows racers to go through it and receive a spin boost. The Master Cycle bike is heavily based off of the Master Sword.

Link also pulls out the Master Sword during two of his tricks.

Super Mario Maker 2
The Master Sword was added in the version 2.0 update in Super Mario Maker 2, where it serves as a power-up only available in the Super Mario Bros. style, obtainable as an alternate form of the Super Mushroom. When the item is collected, it plays the "item get" sound and turns Mario into Link, enabling him to use his shield to block enemies and projectiles, bombs to hit switches and blow up blocks, and a bow and arrow to collect items or attack enemies. He is also able to use the sword to hit enemies, and use a dash attack with said sword and a down thrust in similar fashion to a Ground Pound. When Mario, Toad, or Toadette grab the power-up in Multiplayer mode, they turn them respectively into red, blue, and purple Link, while Luigi still turns into green Link, matching the Link colors from Four Swords and Four Swords Adventures. The sprite of the Master Sword is an edited version of the White Sword from the original game. In night ground levels, Link's bombs walk in the direction they were thrown.

In a similar vein to Superball Mario, when using the Master Sword in the ground, sky, forest, underwater, desert, and snow themes, the music is replaced by the overworld theme from The Legend of Zelda; in the underground and Ghost House themes, the game's dungeon theme plays; and in the airship and castle themes, the game's Death Mountain theme plays. Sound effects are also borrowed from the game. The boss theme sound effect while under the Master Sword's effect is the battle theme from the Family Computer Disk System version of Zelda II: The Adventure of Link, while the final boss sound effect is Shadow Link's battle theme from the same game.

Once Link beats a level, it plays Zelda's rescue theme from the original game with a slightly lower tempo. In castle-themed levels, Link holds a Triforce shard after touching the Axe with the "Triforce collected" theme playing from the original game. The death theme from the original game plays when Link falls in a pit. Several sound effects are also modified when playing as Link.