It's called a "Chromato-Cloak" (Patreon)

Variant of the word Chromatophore, or the cells in cephalopods that allow them to rapidly change color.

I'm thinking of going back in and adding a few details. My plan was for the hallway to be more or less spotless, but I kind of like the idea of some odds and ends being left out.

Candles. Staffs. Maybe a sock?