And then there was that time the United Kingdom's Action Force Monthly decided to do a tie-in story to promote the release of G.I. Joe: The MovieAction Force: The Movie, resulting in a scene where Serpentor gently caresses Destro's metal mask when he hallucinates that Destro is Pythona. Which was, so far as I know, Pythona's only appearance in a comic book until Devil's Due did their G.I. Joe/Transformers crossovers around 2004.
Scans from G.I. Joe: European Missions #6, "As Thick As Thieves!". Story by Mike Collins, art by Robin Smith.