Hi!

First of all let me tell you that me and my friend really like this mod. The burrowing giant worms are especially great.

Now to the bug. So, an Incendiary Spitter Monster appeared and destroyed a few rails and a couple of cargo wagons, but after that it completely froze and didn't move or attack anymore. Also is there a reason why all of the giant monsters spawn with only 1/5 of full hit points?

Hi Carnivale
Good to know you are having fun with those beasts =)
All aliens have an AI driven by the game core. Unfortunatelly, sometimes they get stuck, and after some time, they start moving again. And I don´t know why... I think they like to eat robots a lot. Try to offer some tasty flying robots, with salt and pepper. They will love it.
Monsters spawn with part of its full hit points, depending of the current Evolution Factor and the number of players on line. More players, more HP...