Heard about this strange substance but never seen it until yesterday afternoon, up in the hills near Trawsfynydd, North Wales.
Wikipedia: Star jelly (also called astromyxin, astral jelly, pwdr sêr, star rot, or star shot) is a gelatinous substance, which, according to folklore, is deposited on the earth during meteor showers. It is described as a translucent or grayish white gelatin which tends to evaporate shortly after having fallen.

More info: http://www.bbc.co.uk/scotland/outdoors/articles/jelly/