Driller

The largest subterranean lifeform native to Cybertron, Drillers are not to be taken lightly. Enormous multi-tentacled beasts capable of burrowing through the ground or through buildings with ease, they are capable of great destruction and carnage on any scale. Naturally, all these qualities have endeared them to Shockwave who keeps one as a pet and personal transport.

Description
The Driller resembles a giant mechanical snake or worm and is armed with several tendrils tipped with saws and pinchers. Due to their fossorial lifestyle their heads are drill-shaped, hence their name. While wild-animals they can be tamed and domesticated, as seen with the one Shockwave owned which behaved like a loyal dog to him.

IDW movie comics
Years before the war began, when Sentinel Prime's Autobots revitalized Cybertron by re-energizing the AllSpark, a Driller was drawn to the surface by the fresh energy flowing through the planet. At the outskirts of Thetacon, it attacked some Hatchlings and their protector Starscream. Megatron and Shockwave saved them from the creature, forcing it into retreat, but the beast had left an impression upon Shockwave, who deemed it "magnificent".

At some point before or during the war, Shockwave captured and tamed a Driller—whether it was the same creature he had fought beforehand or another member of its species is unknown—and brought it to Earth with him, where Astrotrain built a cage for it. When its master was about to get killed by Optimus Prime, the Driller made it to Philadelphia and saved him. Ironhide recognized the creature and told Prime that if the Driller is what he thought it was, then they were in a big trouble.

Dark of the Moon film
A Driller, this one partially re-engineered to serve as Shockwave's chariot and warhound, was summoned alongside its master, to attack Optimus Prime when NEST was called to Chernobyl by Alexi Voskhod. This was only misdirection, to ensure that the Autobots did not realize that the Decepticons actually wanted them to find the fuel cell from the Ark located within the facility. After Optimus retrieved the fuel cell from the Driller, Shockwave emerged from it to reveal himself to Optimus, and the pair quickly retreated underground. The experience left Optimus somewhat shaken, and angry with the humans that they had concealed the Ark from the Autobots.

Later on, the Driller was present in Chicago during the Decepticon invasion, proving to be a deadly threat from below, separating Optimus from his trailer and the flight tech it possessed.

It crawled its way in and through a toppling skyscraper by Shockwave's command to flush out Sam Witwicky and his allies, and caused the building to snap in half, the top section slamming onto another building. When the Driller went in to finish the humans, Optimus, with the jet pack and upgraded weapons from his trailer, attacked it in midair. The Driller's reach with its tentacles was hindered by the building as it attempted to fight back, and Optimus counterattacked it by slamming his entire body through its neck, killing it. Its partially severed body crashed to the street below.