Just recently we got the Raptor commander so when I played a game yesterday just to find that a fourth commander was available was well, surprising. seeing as there hasnt been any thread about this subject I guess I will come out and say that it was most likely a bug that allowed me and another user to use this new four legged commander. which I suppose would be considered the Spider commander even though it only has four legs. If this is indeed a bug then I hope this helped in bringing it to light.
he's called Quad_base in the game directorys unit folder and in his .json file he's known as "Quadruped Class Commander" or "awaiting better name" but there is folders for Beast ,, hmm Titan Commander maybe. Raptor Spider
That's about the only (albeit mythical) creature I can think of with six-limbs that walks on four-legs (i.e. quadruped). It certainly isn't a Spider which has eight limbs or a Crab which has ten.
You can still use the commander in the current update, so it was either intentional we could use it or is a bug that hasnt been fixed. the walking style of this commander is pretty neat but obviously tweaks out a little. Thats beta for ya.
Now I suppose the only right thing to do is name the commander after me. after all whats a better name for a commander other than Dirx. now all we need is a lolita commander.
Wow. That's quite the epic new commander. I wonder when Uber will officially announce it. I've confirmed that it is selectable for the newest build (55493) and attached a couple more screenshots to show it from other angles.