What is "star jelly"

Nostoc \Nos"toc\, prop. n. [F.] (Bot.) A genus of alg[ae]. The plants are composed of moniliform cells imbedded in a gelatinous substance.

Note: Nostoc commune is found on the ground, and is ordinarily not seen; but after a rain it swells up into a conspicuous jellylike mass, which was formerly supposed to have fallen from the sky, whence the popular names, fallen star and star jelly. Also called witches' butter.

n. A gelatinous substance that, according to folklore, is deposited on the earth during meteor showers.

Star jelly (also called astromyxin, astral jelly, star rot, star shot or moon poo) is a gelatinous substance sometimes found on grass or even on branches of trees. According to folklore, it is deposited on the earth during meteor showers. Star jelly is described as a translucent or grayish-white gelatin that tends to evaporate shortly after having “fallen.” Explanations have ranged from the materials being the remains of frogs, toads, or worms, to the byproducts of cyanobacteria, to the paranormal. Reports of the substance date back to the 14th century and have continued to the present day.