Decepticon Command Bunker

For a change, a Transformer base not made of a spaceship crashed into the side of a mountain.

Part of the Decepticon infiltration protocol is the establishment of a hidden Decepticon Command Bunker on a planet, from which the invaders can subtly influence events among the native life forms. Once the natives are sufficiently softened up, the Decepticons can start Phase Five, which includes converting the Command Bunker into "siege mode", turning it into a massive fortress.

Fiction

2005 IDW continuity

A Decepticon team led by Starscream established a Command Bunker in Nebraska to mine Ore-13. When they exhausted that seam, they abandoned that Bunker in favor of constructing a new one over a seam in Oregon, and placed the base in siege mode. Infiltration #5 The first bunker was discovered by Machination agent Stoker, who took images of the deserted interior. The images eventually found their way into the hands of Verity Carlo and the Autobots. Verity and her friends accompanied Ratchet and Bumblebee to the Nebraska bunker, Infiltration #3 and ventured inside, unaware that Blitzwing and Skywarp had been sent to destroy the base. Also visiting the base was Megatron himself Infiltration #4 who was extremely unhappy when the two Decepticons destroyed the base with him still inside. He launched an attack on the Oregon Bunker Infiltration #5 and relieved Starscream of it (and it of Starscream). Infiltration #6 The bunker was later attacked by the Reapers and then the United States Air Force. Devastation #6

The Wreckers were attempting to breach a Command Bunker in siege mode on Varas Centralus when they were recalled to Cybertron to help prevent the possible revival of Thunderwing. There was another Command Bunker on Nebulos where Thunderwing eventually turned up, Stormbringer #2 but it ended up abandoned when the Decepticons were either killed by Thunderwing or fled the planet. Stormbringer #3

Games

Transformers: Earth Wars

A Command Bunker is present in the side of the mountain the Decepticon base is located at the base of. Transformers: Earth Wars