Decepticon mobile fortress

The Mobile Fortress is a fortress which is mobile in the Energon cartoon portion of the Unicron Trilogy continuity family.

Apparently this was in Armada, because everyone sees it and goes "OMG, Unicron!"

We have destroyed the fortress that once was home to Unicron.Optimus Prime is reading from a different script, Battle of the Asteroid Belt

The Mobile Fortress flies around, sometimes disguised as a comet. It blows up a lot.

It looks like a turd, which is pretty appropriate since it's extruded from Unicron's mass.

When the animators use the wrong reference art, it's perfectly smooth.

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