i actually think terivgon spam COULD be effective if used right - if you spend 1-2 turns running like mad at the enemy with regenning tervigons with FNP and then spawn youd be able to increase your chances, and anyway you can keep them cheap enough to hav a few fun bits in your army (zoanthropes venomthropes doom of malantai?) it may not be able to take on everything but could take on most with a reasonable chance of winning a 6 wound MC which is a scoring unit is good in anyones book