Squiggoth

Even more impressive than the ork, however, was its mount.
The creature was the largest living thing Mitranda had seen, outside of the Bio-Titans of Hive Fleet Naga. It was a quadruped, dark green in colour and scaled like a reptile. Its monstrous skull bore sharp teeth, some of which were near as long as an adult human was tall, while twin tusks curved first outwards and then inwards from its lower jaw, and a single horn erupted up from between its tiny, ferocious red eyes. Its upper body was covered in armour plate, in addition to whatever protection its own scales would give it, and its legs were the width of an Imperial grade-three standard support pillar.
The creature bore on its back a howdah that appeared to be little more than two captured Chimera hulls crudely welded together and with the roofs removed: since, after all, the monstrous ork within would have had to bend nearly double in order to fit into such a space. The side-mounted lasguns had been removed, of course – las technology appeared to be either not understood or simply shunned by the greenskins, although they did have some powerful energy weapons of their own diabolical devising – and replaced by two guns that looked to be the greenskin equivalent of heavy stubbers. Surrounding the commanding ork were eight others, each larger than the statistical average from observed specimens, and each clad in armour similar to that of their commander, albeit less ostentatiously endowed. There were also a couple of other orks who were considerably smaller, and were probably the beast’s handlers: Mitranda dismissed them as low-priority targets.

Brutal Kunnin'