Xantium

The Xantium is an Autobot ship in the IDW portion of the Generation 1 continuity family.

Does this make it a Wrecker?

The Autobot battlecruiser Xantium transports the Wreckers from mission to mission. It looks like it transforms into some giant robot.

[edit] Fiction

The Xantium served as the Wreckers transport during the events of Stormbringer, taking them from Varas Centralus in the Kol system to Cybertron after being redeployed there on Optimus Prime's order. En route Springer advised Prime that if they couldn't stop Thunderwing they should destroy him along with what was left of Cybertron. Stormbringer issue 2

Don Figueroa said that the Xantium design is based on "Stronghold", a character from his old Macromasters fanfic comic. He also said, though, that if it ever transforms into a robot it will look a lot different.

On the other hand, IDW Editor Chris Ryall has said that the Xantium isn't a Transformer, though this statement could be interpreted in a few different ways.