AI Headquarters

AI Headquarters - is an area in B3313.

Description
It takes place in a large, dark, creepy and rusty labyrinth, shrouded in darkness. Yellow arrows on the walls point the way to the checkerboard floor room where the Core rests. The closer, the more nearby textures will become buggy and the message "DESTROY IT" will appear. As a result, when the player comes very close to the Core, everything will descend into darkness, and the Core will disappear. But in the distance, the old familiar Textureless Mario is already rushing towards the player...

Origins
It appears to be an original creation.

Sounds like the Haunted House theme from the Vanilla Game OST.

Plot meaning
Mario/Luigi seems to have snuck into the AI's lair, which (obviously) pissed him off as his shouldn't be able to find this place. At this time, the Alt AI planted the Core in this place to induce the Mario Bros to destroy it. The AI noticed this and decided to take advantage of the moment...

Leading here

 * Personalization Chamber: With some probability, you will get here through the picture.