Machinations

The Machinations, better known as the Machines, are technologically advanced, mechanized creatures built by the Decepticons as part of Project Zero Hour, an operation intended to wipe out all life on Earth. They typically bear strikingly similar designs to various forms of wildlife, such as avians, ungulates, and even dinosaurs. Apparently, they were in development long before the Transformers arrived on Earth. Some of the machines were specifically designed for combat, such as the Scarab and Khopesh.

Other machines are much rarer, such as an ancient device identified as "Metal Devils."

Creation
The first machines were created on Cybertron by Shockwave under Megatron's command. They were intended to be a secret weapon for future use against the Autobots, though their existence was known only to a select few Decepticons. While many of these machines were created as domestic servants for the Decepticons, Shockwave also begun to develop machines built for combat, two of which were the Scarab and Khopesh, heavily-armed robots that could supplant entire armies, convert biomass into fuel, and replicate themselves allowing them to operate indefinitely.

Project Zero Hour
After Optimus Prime was defeated and forcing the Autobots off Earth, Megatron activated "Project Zero Hour." Hacking into government systems, Soundwave called the machines to Earth and programmed them to begin attacking the local population. The machines replicated faster than they could be destroyed, and begun operating as a swarm. Soon, a full-fledged war between humanity and robots began, costing millions of lives (including the President) and immense destruction. Despite humanity's best efforts, the swarm could not be contained, and within three months, the entire country had been destroyed, with the remaining Humans forced underground. Megatron then authorized the construction of a program called H.A.D.E.S., which was intended to send the machines to the remaining countries as to wipe out the Humans once and for all.

Deactivation
Despite being outnumbered, the Humans rallied behind Tessa Barry and William Lennox, both allies of the Autobots. Resistance troops begun to attack the machines across the country, even targeting Decepticon facilities that were manufacturing the machines. Eventually, the Autobots returned to Earth under a restored Optimus Prime, who engaged Megatron in battle. Meanwhile, Shockdrop managed to defeat Shockwave and cracked the encryption codes to shut down the machines. Megatron was severely injured after Tessa shot him with a powerful Cybertronian weapon, but was then taken away by Starscream as the Decepticons abandoned Earth. H.A.D.E.S. was shut down simultaneously by a joint Autobot/EDC assault led by Tessa, thus stopping the Apocalypse.