How to make this extra room cute in a renter-friendly way?

Not sure what to do with this extra room (not even really a room because there aren’t any windows) to make it cute. We’re renting in the bottom level of a house and will likely be here at least another two years so I want to make this room cute for guests. I plan on putting in a twin bed frame that I already have. Any renter-friendly ideas for making this room cute? Note: we can’t change the ceiling in any way no matter how much we want to 😵‍💫 And please ignore the weird decorations, my partner wanted to put all the creepy stuff we have in this room for fun!

TIA!