Visitations
The opening act of Reaching the Omega Point.
This tongue-in-cheek BW story was only presented as a live reading at BotCon '98. It's highly satirical, with self-referential and fourth-wall-breaking humor. (For instance, at one point David Kaye, reading Megatron, shoots and "kills" audience member Ben Yee.) However, looking past the comedy, the core plot goes as follows:
Set in season two, Packrat and Onyx Primal (another Maximal treated as an "unseen extra" from the cartoon), scouting Predacon territory, stumble upon a strange device. But they're suddenly attacked by Fractyl and Vice Grip (a Pred with the same apparent "unseen extra" status as Onyx Primal), who were looking for the "artifact." During their battle, a "shadowy figure" appears, swipes the device, and vanishes. Then some of the main BW 'toon Maximals show up and help beat the Preds. But in comes Antagony, who demands the device. Before she can attack them, though, Megatron flies in. She reacts violently to him, claiming to have searched for him across the cosmos. But she loses the ensuing fight, and Megatron takes her captive.

