Warworld

The Warworld is a vast, spherical Decepticon battle cruiser created by the Decepticons under the command of Bludgeon. Built from technology stolen, scavenged, and forcibly taken from a variety of alien sources, this patchwork ship is a force to be reckoned with, covered with armaments of all sizes, from small guns to the huge primary cannon whose lens dominates the front of the vessel.

Sometimes there are lots of it.

Marvel Generation 2 comic
Bludgeon's purpose for creating the Warworld was as a ship for stealing energy and other resources throughout space (including those from the Jabbi-Ko, Karkan, and Szorian races). It was originally his flagship and host to his army of Decepticon clones.

When Megatron battled and destroyed Bludgeon, he took command of the ship, cargo and crew included. The Warworld was involved in many Autobot conflicts.

Starscream stole the Matrix and used its power to combine himself with the Warworld. He reshaped its interior, battled Jhiaxus's troops, and tortured Megatron and Optimus Prime. But the Matrix's essence started to turn him from his evil ways. Starscream was so scared of becoming good that he did not put up any resistance when Optimus Prime and Megatron took the Matrix away from him.

Fleetway Generation 2 comic
The Warworld serves as the Decepticon mothership.

Regeneration One
Bludgeon's forces travelled in the Warworld to the planet Torkulon, where they eradicated the native population. Soundwave, the leader of Cybertron's "Neo-Decepticons" met with Bludgeon aboard the Warworld above Cresta Superior to witness a demonstration of the latter's new Blitz Engines as they... eradicated the native population. Following an agreement between the two Decepticon leaders, Bludgeon turned the Warworld towards Cybertron.

Thanks to Soundwave, all of Cybertron's long-range scanners were out of commission so Cosmos, performing reconnaissance for the Autobots, was the first to notice the Warworld's arrival... and then it promptly obliterated him. With the Blitz Engines running amok on Cybertron and the Warworld looming in the skies overhead, Perceptor quickly deduced Bludgeon's war machines were being powered powered by Matrix energy and so Kup and the Wreckers were dispatched to infiltrate the giant starship. Meanwhile, Bludgeon was persuaded to unleash some of the Warworld ' s ordnance on the planet below, selecting the Autobot hero Ultra Magnus as his primary target.

After allowing his troops to join in the battle on Cybertron's surface, Bludgeon elected to take out the Wreckers aboard the Warworld himself, using his stealth and Metallikato skills. Pursuing Kup through its interior to the bridge, he was surprised by the emergence of Rodimus Prime from Zero Space and quickly bested by the Autobot leader, who threw him through the bridge window to fall to the planet below. Subsequently, the Warworld came under heavy fire from the Ark under the control of Starscream and Shockwave. As Rodimus Prime and the Wreckers evacuated the Warworld it exploded above Cybertron, eliciting cheers from the victorious Autobots below.

e-HOBBY comics
When the recently departed Ultra Magnus became aware of a massive fleet of Warworlds Galvatron II was building, he used the Reconfiguration Matrix to resurrect himself in a new body.

2005 IDW continuity
At some point in the Great War, the Decepticons had amassed a fleet of War Worlds. A single ship of the class was regarded by Starscream as having enough firepower to destroy multiple planets. Skullcruncher and Krok served together on one of them. The Autobots successfully bribed the notorious Phase Sixer Black Shadow half a billion Shanix to blow up the fleet, leading to his being wanted by the Decepticon Justice Division.

Later, aboard the Lost Light, Chromedome noted that Trailcutter's Nightmare Fuel could push a Warworld into hyperspace.

The renegade Decepticon Deathsaurus used a stolen and rather grubby Warworld as the flagship of his fleet.

The Space Knight Livia was familiar enough with Warworlds that she proposed the mysterious Unicron might be one. A number of Warworlds were employed by the Decepticon Vengeance Division in their failed attempt to destroy Unicron, subsequently being warped into Unicron's service and acting as his heralds during his attack on Cybertron. Unlike the Worldburners and Worldsweepers however, the Warworlds were all destroyed.