Crown

Crowns are the objects seen in various games to indicate the winner of a previous round, or the leader of the current one.

Super Mario 3D World
They first appear in Super Mario 3D World, where the player in first place in score at the end of a level will gain the crown for the next level. They can be knocked off players as well, whether by enemies or other players, and give an additional 5000 points to players in possession of the crown at the end of a level.

If multiple players are tied for first place at the end of the level, nobody will receive a crown.

Mario Kart 8
Crowns reappear in Mario Kart 8 to indicate the current leader of a race on the minimap.

Mario Kart 8 Deluxe
Crowns reappear in Mario Kart 8 Deluxe, where they now appear in Battle Mode both in the world and on the minimap indicating the current leader.