Doomsday

The Doomsday is a Decepticon spaceship in the Unicron Trilogy continuity family.

The Hyperion (left) versus the Doomsday (right)

The Doomsday was the Autobot flagship 4 million years ago.

(The name 'Doomsday' comes from a Japanese sourcebook, the ship was not named in the American episode.)

Fiction

Armada

The Doomsday took part in the Battle where the Mini-Cons fled Cybertron. At one point, it is engaged in a direct confrontation with the Autobot flagship, the Hyperion. First Encounter

From Teletraan I: The Transformers Wiki, a Wikia wiki.