It is Tier 5 Communications Array. So what is different between the ultra rare carrier pets and the others is only evident in the Scorpion Fighter since only the devs know which pets are available and what the stats are for the others. The rare scorpion has Plasma Pulse Cannons and Plasma Torpedoes. The very rare scorpion has Plasma Pulse Cannons, Dual Plasma Cannons, and Plasma Torpedoes. The Ultra-Rare Scorpion has Plasma Turret, Dual Plasma Cannons, Plasma Torpedoes, and Torpedo High Yield. Basically the way that these are different from rare and very rare is that they have an extra skill, weapon, or buff over the others.
My Slavers seem to have no problem dodging plasma torpedoes most of the time.
If I have to guess then I'm betting my Slavers at the Fleet level will be either able to steal something new, like fleet marks and or beam over load or one of the mine powers. This is just a guess based on the ultra rare socropian fighters.