Cappy
Cappy is a new character in Super Mario Odyssey, he appears alongside Mario in Super Smash Bros. Ultimate as a taunt and he also appears as a spirit.
Character Origin
Cappy was introduced as Mario's latest companion in Super Mario Odyssey, with the motivation of helping him rescue Princess Peach and his sister, Tiara. His signature ability is notably being able to be thrown about at his own will, and posses several entities in the Mario universe. In Super Mario Odyssey, Cappy can be either fully part of Mario's abilities or be separately controlled by a second player. He also changes his appearance with the hat of Mario's choice, with his eyes appearing in the center to show off that he's there.
Super Smash Bros. Ultimate
In Super Smash Bros. Ultimate, Cappy appears cosmetically within Mario's moveset while using Up-Special, Super Jump Punch. He also appears as one of Mario's taunts, where he flies above his head shortly before sitting back atop Mario's head.
Cappy also makes an appearance as one of the many Spirits obtainable throughout the game's Adventure Mode: World of Light. He's listed as a Support Class Spirit, giving the character the "Strong Throw" attribute. This is likely a reference to the use of Cappy in Super Mario Odyssey, being thrown frequently in Mario's adventure.