Grendel Gambit

The Grendel Gambit was Galvatron's plan to defeat the Human Confederacy, who forcibly imposed the Allowed Zone on the Transformers.

It didn't work. It really didn't work.

Fiction

Beast Wars: Uprising

After the establishment of the Allowed Zone, Galvatron - with his sanity bolstered by becoming a Triple-Threat Master - devised a cunning plan to deal with the pesky humans. A Brush With Infamy–Prologue

His plan was to disguise himself and his troops as humans, somehow, and muster a huge invasion fleet, to sneak past the blockade. Mankind saw right through it, and after one attempt at a last stand by Galvatron, blew the fleet up, and took their resultant anger at the attempted deception out of both Decepticons, Autobots and neutral Cybertronians alike. Micro-Aggressions Book of Logos Despite what history recorded, Nucleon, one of Galvatron's binary bonded partners, believed that the Gambit had very nearly succeeded in destroying humanity's empire. A Brush With Infamy–Prologue

The events of the Gambit were prophesied in the Book of Logos. Book of Logos

Notes

• The Grendel Gambit was mentioned in "A Brush With Infamy–Prologue". It was detailed further in the hidden text story, the "Book of Logos", albeit in the pseudo-religious wording of the text. However, the details do match the description and timeline given in "Micro-Aggressions" of Galvatron's last attempt to get at mankind going to crap.
• An additional event was mentioned in "Intersectionality", the Great Push, which was the last last battle with mankind between 'Cons and mankind. The stories don't make it clear the exact relationship between the two, whether the Grendel Gambit was part of the Push, the cause, or if it's just another name for the same term.
• Its name comes from Grendel, the main antagonist beast from the Old English poem Beowulf.