Patra

Patra is a Decepticon-allied Nebulan from the Generation 1 continuity family.

You can't see me!

_{This character has no official visual representation in any Transformers product or media... yet, at least.}

Patra, according to reports, is a Decepticon-allied Nebulan Powermaster and ophiologist who transforms into the engine of Clio.

Fiction

The cover of Venus, a trans-dimensional magazine for Decepti-femmes, invited its readers to decide who was deadlier: Clio or Lyzak. The AllSpark Almanac

The state of Patra's existence remains mildly sketchy. Originally, the only mention of Clio and Patra was in Blaster's letter column in the UK comic book (which told the "true" tale of the Transformers), replying to a letter from a human comic-reader who had seen a TV commercial for the Renault Clio car that had the vehicle transform into a robot. When the reader suggested the Autobots recruit it, Blaster lamented they'd been beaten to that punch. Blaster could very well have been making it all up as a joke; the Transformers who have answered human mail tend to be jokesters or flat-out insulting towards their readership.
- Subsequently, Clio's existence has been confirmed by the Allspark Almanac, which namedropped her on the cover of Venus, a trans-dimensional magazine for female Decepticons. While this does not confirm the existence of Patra outright (because she is not mentioned), we can charitably assume that the existence of Clio confirms the existence of Patra.
"Clio-Patra", get it? And the snake thing? Oh, you clever Britons.
A driver is barely visible in the Renault Clio commercial that Clio originates from. We may as well go crazy and assume that's Patra.