My party took it out in one round, no, sorry, let me rephrase that ONE MEMBER of my party took it out in one round.
With a combination of stacked feats and fist bindings that allowed him to apply a flaming effect to his unarmed atacks.
The party's Monk moved round and dropped down to it, intending to scout out the hole ahead of the party, he landed right in front of it.
It reared up, he beat it on inititative and proceeded to beat the ever loving crap out of it with a several criticals.
It didn't even have time to whimper before it was so much Hydra burgers for the trip.
Monks are evil, EVIL!!!.
*Grumbles*