Urple prose is overwritten prose smothered until it is not purple prose anymore, but urple. Urple prose tries to be beautiful, but ends up being unavoidably ugly and often pretentious. Urple prose is most commonly written by badfic authors who try to create descriptive prose but go overboard with adjectives, similes, and metaphors. The result is over-descriptive writing that does not flow well.
Mary-Sues are commonly described with urple prose. Particular attention is paid most often to hair, eye colour, and clothing, in phrases like "a single clear, glimmering drop of pure diamond slid down her perfect, rosy cheek, smearing red mascara as it slid down her beautiful cheek". Excessively urple prose seems to create an Urple Cloud, though this has only been observed on one occasion and is still being investigated by the Floating Hyacinth.
Agents exposed to an excess of urple prose may develop Urple Fever.