Textureless Mario Anomaly

The Textureless Mario Anomaly is an anomaly only known to exist in individual personalized copies. Encountering this anomaly implies future bugs and crashes.

While this anomaly is active, the HUD and screen will flicker. Various 3D objects, the pause screen, and other map geometry will appear to be black. When the objects are interacted with, the game will freeze or crash. In more personalized copies, an error screen will appear instead. Water textures will also appear to be completely invisible. All music and sound effects are muted while the anomaly is present.

Documentation
Footage of this anomaly occurring can be found in a video made by SwankyBox on his channel SwankyZone.

Greenio's Tapes
This anomaly appears on one of Greenio's tapes, specifically in 11.15.95, where he briefly appears in 1:20 in the room with the trapdoor to Bowser in the Dark World. The screen goes black and then this anomaly shows up close to the camera in the black background with the message "I'M NOT HAVING FUN" then his red and blue color turn black and the screen goes black.

Theorising
Considering that the only available footage of this anomaly was from a ROM hack where all the objects are replaced with coins, it's likely that Nintendo's adaptive A.I. is trying to reprimand and punish the player for tampering with the game. It could also be a anti-piracy system.

A hidden message within the footage of the anomaly seems to imply that it is somehow connected to Wet-Dry World.