Rather nasty seminightmare ...
I dreamed that I had some sort of worm infestation which I could clearly see and feel squirming around just under the skin of my thumb. From time to time it would burst out and writhe on the pavement in front of me: when it did this it was much larger and (oddly) looked a bit like one of those elastic ropes with hooks on each end.
I'm pretty sure this was brought on by a mild RSI tingling in the pad of the thumb. I'm less sure why I felt compelled to share it with the world :-)