Vervoids
Vaginal penis plants from space that ejaculate grey smoke from their face urethras and can allegedly transform humans into Vervoids using their pollen, similar to Varga Plants, but for whatever reason choose never to do so.
Podcast
C146 Terror of the Vervoids (Trial of a Time Lord: Part Three)
A WHO-dunnit with provocative space plants that flounders a little in the mystery department