Ok so let's analyze the damage potential against, say, Ironjawz. This is probably biased toward the Ark of Sotek a bit because Ironjawz have pretty good saves, but let's just do it that way to compensate for my personal bias toward the Solar Engine. I'll assume the Ark gets curse of fates. Both get the same Javelins attack and the same bludgeoning tail. So this will be a slight numerical advantage for the Ark as well, because in the first round the Solar Engine Bastiladon will not be in range for either. Here are the numbers for the SE: 2d6 attacks, that's seven on average. 4+/3+/-1/2 So half of those hit, which is 3.5 66% of those wound, which is 2.3 With the rend that means Ironjawz have a 5+ save, so 1.5 actually do damage. That means against a 4+ save we get 3 damage (4.5 against Chaos Demons) on average, most of the times on one unit, at a range of 20". Here are the numbers for the Ark: I'll assume it makes that charge. With four units in range: 8 dice hit. There is no hit or wound roll. So we cause eight mortal wounds. As long as our opponent is not playing Death (or another army with a mortal wounds save) this is pretty strong. Since we attack first, even if they are focussing our bastiladon down there will be at least 9-10 wounds on enemy units on average. (if we assume we hit once with our tail and also maybe with one Javelin or so. Now this looks good for the Ark. Especially since it will also hit armies with good saves like SCE or Ironjawz. There is one thing that affects our tactic a bit though: The probability of an Ark of Sotek actually removing a unit is pretty low, except with loads of luck, since we will be spreading our mortal wounds equally to the dice numbers. It doesn't matter if there are six units next to it, or just one. On average each unit will receive two mortal wounds. Even with a very low bravery on that unit this is unlikely to cause models fleeing by battleshock. The Solar engine Basti is causing its wounds on one unit. So it is more likely that it will cause a battleshock (probably not against Ironjawz, but against armies with single-wound models it might). Now for buffing: You can improve the Solar Engine Basti's wound output by a good amount using one or more of those: 1. Stegadon (re-roll hits of one) 2. Astrolith Bearer (rerolls of all hits) 3. Skink Chief (+1 on hit) 4. Thunderquake (both swift and savage are useful (re-roll hits or wounds). Also if you play Thunderquake it is relatively likely there is a Stegadon near anyway.) 5. Curse of Fates (improve one of your failed rolls in each phase, so you can use it both for the tail in melee, and to improve a wound, hit, or the number of attacks roll. The latter being probably the best option if you rolled a 1 or 2 on one of the dice) So it is pretty easy to buff it to do ~5 damage per round (by choosing any two of the above buffs), and suddenly battleshock becomes more interesting. The Ark of Sotek Basti's "tide of snakes" profits from none of the above, except #5. You can alter a single dice. Statistically that means that you will do one wound more. Keep in mind though that this will only work for one round if you teleport it, and you cannot buff your tail because the tide of snakes takes place in the combat phase, and you only get to change one roll per phase. Also since you are teleporting into a group of enemies the Basti will probably die in round one or two. Still not bad at all, actually better than I thought. I still don't like not knowing what I will hit.