I'm open to any suggestions anyone might have on how to beat thst thing. 2s to hit 3s to wound, 50 models in it...
Assassinate the mage and shoot until they crumble. Haha! Sorry, not much advice there. Combination of magic shooting and some heavy hitters, but you got to make sure they don't come back.
Plus, remember that they may have bravery 10, but they're not immune to battleshock. Shoot 'em and they will also flee.
So we played a team game today. Chaos and seraphon ( i know, right?) Vs 2 death players, one with the 50 model zombie tarpit. We played 3 places of power. We won by playing to the mission, and in the end all my partner had was his greater demon of nurgle. I had my Scar vet and skink priest. One of the death players was all but wiped out and mr tarpit lost 2 zombies, i put 11 wounds on his terrorgeist with my scar vet and dropped his mortis engine.
We played 1000 points each. I had scar vet on carnesaur with quicksilvet potion and legendary fighter leading a firelance battalion of 3x5 knights, a skink star priest, 5 chameleon skinks and 10 skinks w/ blow guns. The scar vet killed a zombie dragon, a mortis engine, put 11 wounds on a terrorgeist in exchange for 8 wounds.
I've always just focused the group for a turn or two. As others have mentioned, battleshock is the most efficient way to down them. If you break the bravery threshold, each kill is effectively worth two. If you down them past the horde bonuses they become useless very quickly and you can focus on bigger and better things
Also you can get a flame thrower stegadon and hail Mary it into them. If you can survive a round of combat or get to within 3" at the start of a shooting phase you will be rolling a boatload of dice and vaporize them pretty quickly. If you can get a mystic shield on it before its gonna take 8.03x10^83 attacks back all the better. Combined between horns, stomps, and flamethrower a steg can help you tremendously against stuff like this.