pocketpadfoot:

I think that the whole slimy interior of the Slytherin dormitory is probably an illusion charm cast in case intruders enter the dormitory. Only if you’re sorted in Slytherin or a close friend of a Slytherin you can see the luxurious silver lined couches with soft green plaids to snuggle under and forest green tapestries and the fountain in the middle with the clearest water that tastes like whatever you want when you fill your glasses.