Should be obvious.
GN forgot to remove the beta elements such as this.
Biting it anywhere in sublevel EE will "lock" up the game, rendenering it unplayable because the game never returns Mario to the OW.
- The boss door leads nowhere.
- Oh, and the Cheep-Cheeps (the Icegoom redrawn Blurps) need to have their Ex-Animation disabled because they have proper graphics.