So an upcoming mission in one of the games I am running is Tremors (the movie) inspired, with Raveners as the primary bad guy, though with rippers mixed in, and I am debating tossing a mawloc too. I was just wondering if any of you have tips on how to make this a successful mission?

Could you throw in an ordo xenos inquisitor with a massive ton of weapons?

Assuming a kill team size of 5 and rank one, you should go with a single Mawloc. It will be terrifying (But ignored because Space Marines) it will be really tough to get them to figure out how to do it. Raveners won't be scary enough unless you have a bunch of them.

I have a team of 2, but they will be rank 2 at this mission. Thsts why I am leaning on raveners a bit more. Have there been stats published for Mawlocs anywhere?

You could take carnifex stats and upgun them a bit in HP. Then use the ravenor style flavor for it. But two rank 2 VS a mawloc will be tough unless they have good gear. I would saw it's a game of terror where they are running around and struggling to survive watching all these other people getting eaten. Then they find a stockpile of demo charges and one has to act as bait to bring him into a trap.

Two rank 2 marines will get slaughtered by a Mawloc. Trust me. These things eat squads and tanks. Two marines are like an appetiser.

For a start this thing will have massive armour and toughness, probably hide armour at AV10 with a TB of around 12 so in order to even scratch the thing you're looking at 22 points of damage. That negates bolters and most swords. Then the wound count would be something like 90-120 given the size and it has around six on table top.

It's S bonus and weapons will do horrifying damage to a marine. I'm sorry but unless you've given them very good gear to kill it and/or detect it then you're going to have a massacre on your hands in seconds.

This is precisely what I had foreseen, which is why raveners come to mind as the most likely candidates.

For stats, if I do go mawloc, since it is evident that FFG hasn't published stats, I would use trygon without a bunch of the abilities, and I would tone down the strength and probably wounds.

The idea is that it would be a moon base used by Ordo Xenos for resupply. The Kill Team are en route to aid an inquisitor on a task and stop there for whatever. Still working on how the nids get there. The big question I still have is can raveners provide the experience I am looking for? I suppose I could design an immature mawloc, one that has yet to grow to full potential.

Pages 187 and 188 of the Jericho Reach book has rules for the Mawloc.

Mawloc... Interesting idea but I agree with Calgor Grimm. They WILL kill any unready enemy and come on it ruins the fun if you know what you are up against. Raveners are probably a better choice for Rank 2 Space Marines.

How about the planet that the moon revolves around (if you have a planet) was attacked by a hive fleet of some sort. They were driven back but the planet is now a dead world. Depending on how big the moon is a part of a hive ship crashed into the moon the exact place where the core reactor of the moon base is. The tyranids quickly made tunnels but they were cleared out entirely by the Inquisition. Or so they thought. Deep down in the moon base a small group of tyranids grew and now they are ready to bolster a long dead attack. Yes they think that the planet is still being invaded. The arrival of the Inquisitor somehow galvanizes them to attack. Imagine the Inquisitor is carrying a relic that is connected to tyranids or the arrival of the space marines has somehow affected the tyranids.

Here is an idea to help, please feel free to tweak it if you like it.