They were the recurring themes (for some reason, don't know what Freud or Jung would have made of them) of my childhood nightmares which I had on a pretty regular basis and made me frightened of going to sleep as a cub. The hands were mainly indoor terrors but the sinky bits were generally an outdoor affair though often there was a certain overlap in that I was being dragged down under the earth by some unseen horror. Often too in area surrounded by other people who I witnessed suffering the same fate. A vivid imagination does have its drawbacks! Bed for me was unfortunately unsafe place, though I never had the misfortune of having it turn into a boat whilst I was in it.