DW Monsters: Gelth

The third story in the revised series is The Unquiet Dead, for which the alien menace are the Gelth. They are a one-off monster in the TV series, and, apart from a few minor mentions here and there, have only appeared once since, and that in a short story, rather than anything more substantial.

Description and Biology

We are told that the Gelth were originally regular organic beings. They somehow lost their physical bodies during the Time War, becoming gaseous instead. How this would work is obviously unclear, but, in fairness, we have little idea from the TV series of how exactly the Time War was fought or what the weapons brought to bear in it were capable of.

DW Monsters: The Forest of Cheem

The second story of the modern show is The End of the World, which features quite a few different aliens. It’s difficult to say too much about many of them, however, either because they are represented only by a single individual (the Moxx of Balhoon), they aren’t really aliens (the Adherents), or both (the Face of Boe and Lady Cassandra). This leaves only the Crespallions, who don’t seem all that different from humans, and the Forest of Cheem.

The Forest have not appeared again in the TV series, but have returned in a couple of stories in the audio anthology Tales of New Earth (which reveals "Cheem" to be the name of a planet to which they were transplanted), and occasionally in the comics.