Battle Arena Pad
From the Super Mario Wiki
Battle Arena Pads are steel pads with a headshot of King K. Rool. It's the hosted way to a battle pit fight with many of the world's Kremling enemies. This is the way to win the Golden Crowns. Each level has one Battle Arena Pad, with the exception of the overworld DK Isle which has two. They have only appeared in Donkey Kong 64.

