Creepy experience last night

I would think you were possible experiencing some sort of sleep disorder like exploding head syndrome. The music box seems like maybe you were having a mild sleep paralysis episode. I experience both those things routinely and it always sucks. You never fully get used to it. Your cat was probably alerted by your sudden movements.

“ Exploding head syndrome (EHS) is a condition in which a person experiences unreal noises that are loud and of short duration when falling asleep or waking up. The noise may be frightening, typically occurs only occasionally, and is not a serious health concern. ... It is classified as a sleep disorder or headache disorder.”