I had this a few times when I was really young, probably around 7 yrs old or so. Super bizarre perception distortions, it was really scary. The bed and my legs would stretch out really far, my fingers would become cartoonishly huge and swollen or tiny. But the worst part by far was the distortion of time, my experience could move in fast-forward, like 10x speed.

I think around after puberty these things stopped happening. The developing brains of children can be so wild. I think it's a temporary form of synesthesia that happens as your synapses are developing and pruning.