Companion

 is a Tier 5 Tank that upgrades from Overgunner and Barrage at level 60.

Design
The looks similar to the Gunner, but it has a Spawner on the back of it.

Technical
Like other Sidekick Tanks, the 's spawner spawns a single Gunner minion. This minion is fully controllable.

Trivia

 * This is the only Sidekick Tank that doesn't upgrade from a Hybrid version of the tank it's based on. This is likely because a Gunner Hybrid was never made.
 * This was actually untrue at one point due to Barrage being added to XYZ, but in the current public version of the game this statement still holds true.