BORG STARSHIP - Rogue Borg ship

In late 2369, in the two-part TNG episode "Descent", a group of rogue Borg began attacking Federation outposts and colonies in several outlying sectors with a new type of vessel, informally known as the rogue Borg ship. This unusual design was asymmetric, totally unlike the previously encountered Borg cube. However, the vessel was still heavily armed and massively armored, and capable of great destructive power.

Only one ship of this type has been observed; the ship attacked the research outpost on Oniaka III, as well as the MS-1 colony, using previously-unknown transwarp conduits to appear suddenly over the target and launch a quick attack.

A schematic variant of this design was briefly seen in the Star Trek: Voyager episode "Scorpion, Part 2", which recounted the brief alliance between the Voyager crew and the Borg in their fight against Species 8472. Referred to as a "multikinetic neutronic mine", the drone Seven of Nine proposed it to Captain Janeway as a high-yield weapon for delivering enhanced nanoprobes after having deemed Starfleet photon torpedo as insufficient.

This design is also seen in the game series Star Trek: Armada, which refers to it as an 'Assimilator' class. Its function is to assimilate or destroy any alien ship or station it encounters. However, this is not canon.