[ Ella carefully navigated her way into Dorian's room until she reached the closet. Resisting the urge to wrinkle her nose a little, she peered in curiously, and then followed his glance up. ]

I... don't think that's mildew...

[ It didn't even really smell mildewy. She reached up cautiously, to touch two fingers to the stuff -ew-. ]

Actually, it looks more like how the wood warps from darkness taint. My floor looked like this a few months ago, when some of that darkness stuff seeped in after hours. You might want to check on the protection for your apartment. ]