In my continuing quest to get more big bugs on the battlfield, I present the Trygon and the Mawloc. In working on the big bugs, I also have a game design thing to talk about. I seriously considered rolling all of these big bugs into a single warscroll much like I did with the various tanks. For example, I rolled the Basilisk, Hydra, Hellhound, and so forth all together in a single "Artillery Tank" warscroll for the Astra Militarum. The reason for this was that I didn't see anything that actually made these tanks unique. All they had was different weaponry, which is easy to do on the warscroll, especially using the Tactical Weapons ability that I cooked up for Imperium units.
When I approached the big bugs, the first question I asked was "what makes this bug unique?". Honestly, aside from the Exocrine and the Hive Crone, I've been able to come up with answers to that question so far. The Exocrine seems a lot like the Tyrannofex, just a big bug with a big gun. The Hive Crone and Harpy seem to be differentiated only by their desire to feed/lurk, so I'm actually probably just going to consolidate them, but since the Exocrine is on a different body than the Tyrannofex, I gave it its own rules.
Anyhow, the point of all this is what I like to call "apples and oranges" game design. It is my opinion that one of the best ways to make interesting game mechanics is to give the players an option between an apple and an orange, that way you won't have to worry so much about players trying to pick between two apples one of which is better. It's my own way of ensuring balance, and I'll give some more details below with the Trygon and Mawloc.
The Trygon and Mawloc come from the same kit and do some of the same stuff. Obviously, GW came up with this "apples and oranges" situation before I did, but I think it's important to recognize it and accentuate it. In this case, the key abilities are "Subterranean Assault" for the Trygon, and "Terror From the Deep" for the Mawloc.
Subterranean Assault simply lets the Trygon set up anywhere during a hero phase with the traditional 9" bubble from enemies. It's very straightforward, I'll probably put it on the Raveners warscroll someday when I get to that.
Terror From the Deep does almost exactly the opposite. It requires that the Mawloc be placed within 3" of an enemy unit so that it can earthquake them. Unlike the Trygon, which pops out and shoots people, then probably fails its charge roll, the Mawloc is born directly into combat. That is what I mean by apples and oranges game design. The Trygon actually dishes out a not insubstantial bit more damage (even when you include the earthquake), but I don't have any worry about players always choosing one over the other because they do wholly different things. The Mawloc might not be as good an orange as the Trygon is an apple, but if a player wants an orange, they know where they can get it.
One last note on the Trygon, I'm sure some people might wonder "what about the Trygon Prime?"
Someday when I write some warscroll battalions for these armies, there will be one that lets Gaunts and Raveners pour out of the Trygon's burrowed hole in the ground. On that day, the Trygon in that battalion will gain the Synapse keyword. It just seemed like a mechanic that belonged on a warscroll battalion rather than a warscroll. However, if you've modeled your Trygon as a super cool Trygon Prime, you have my permission to play them with the Synapse keyword.