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 here.

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 may hint to Wet and Dry World. It is possible that Wet and Dry World is actually Stanley's brain, and Stanley wants to "play" with the player.