Unused Level 3

Unused Level 3 (or Donjon/Funhouse) is an unused level found in the July 25th 2020 leak. It is some kind of maze-like circus level with no objects or enemies whatsoever. It also uses the Placeholder texture (Pink and green spot texture) and tons of other unused textures like some kind of moonlight texture. It was documented by Marionova64 on July 26, 2020.

Theories
Kinopio is the Japanese name for Toad. 3KINOP appears to have a shortened version of that word in its name; this could mean that the area would have contained Toads. Since it is a indoor location, this may hint that this area might have actually been an early version of a room inside the castle, since Princess Peach's Castle was also the only area in the game that was home to Toads.