Carphology refers to the movements that delirious patients sometimes make, as if searching for or grasping at imaginary objects, or picking the bed-clothes.
Not a word that’s likely to be in most people’s vocabulary, nor indeed one that often appears outside large dictionaries. It comes from the Greek karphologia, a compound of the two words karphos, straw, and legeln, to collect. So it means to act as though one was picking up bits of straw, a neat description of the involuntary movements sometimes seen in delirious patients. Brande’s Dictionary of Science of 1842 described it as “an alarming symptom in many acute diseases”.
All the dictionaries I know of that include carphology also refer the reader to floccillation (and usually the other way around, too, making one of those infinite loops that sometimes turn up in even the most scrupulously edited works). This is the Latin equivalent, formed from floccus, a bit of wool or straw, which has also given us the sense of flock that refers to finely-chopped cotton or wool, as in flock wallpaper. There is an even rarer verb to floccillate, meaning to twitch aimlessly, which I can’t find in any dictionary at all, though it does turn up in Samuel Beckett’s Watt of 1959.