Super Smash Bros. series games consists of crossover fighting cameos, which have united characters from games like Super Mario Bros., The Legend of Zelda, Pokémon, Final Fantasy, Sonic the Hedgehog, Minecraft, Dragon Quest, Persona, Metal Gear Solid, Street Fighter, and Fire Emblem. Super Smash Bros. does have a few unique characters to call its own, in the form of its bosses.
The boss of the original Super Smash Bros. was Master Hand, who was a floating gloved hand that assembled the characters at the start of the game. Super Smash Bros. Melee introduced Crazy Hand, who is the left-handed version of Master Hand. The other bosses from the Super Smash Bros. series include Tabuu from Super Smash Bros. Brawl, Master Core from Super Smash Bros. 3DS/Wii U, and Galeem/Dharkon from Super Smash Bros. Ultimate. Master Hand has appeared as a boss in every Super Smash Bros. game and is even briefly playable in the World of Light mode in Super Smash Bros. Ultimate.
The official ed a trailer for Kirby's Dream Buffet, which is an racing/party game, where Kirby races on stages made from sweets, while eating as many strawberries as possible. The trailer for Kirby's Dream Buffet featured different variations of Kirby, as well as several Waddle Dees, who are likey U-controlled racers, as their appearance is identical. The Kirby's Dream Buffet trailer also featured a surprise cameo from some of the Super Smash Bros. bosses.
Kirby's Dream Buffet Features Master Hand From Super Smash Bros.
The Kirby's Dream Buffet trailer includes Master Hand and Crazy Hand, as they are seen performing the count down to the start of a race. It might seem like an odd move to include Master Hand and Crazy Hand in a Kirby game, but this isn't the first time it has happened, as Master Hand of Super Smash Bros. was actually a boss in Kirby and the Amazing Mirror. The two series both share a creator, as Masahiro Sakurai is the brains behind both Kirby and Super Smash Bros., so it makes sense that the first original character from Super Smash Bros. would have a home in the Kirby universe.
It's unclear whether Master Hand and Crazy Hand have a bigger role in Kirby's Dream Buffet, as they are only seen counting. Kirby's Dream Buffet is both a racing game and a party game, and it features power-ups that deal damage, so it's possible that the hand duo could act as bosses in the game. It's also possible that Master Hand from Super Smash Bros. could act in a similar manner to Lakitu in Nintendo's Mario Kart series, by helping fallen Kirby back onto the stage in Kirby's Dream Buffet.
Source: Nintendo UK/YouTube