The Alien Arc

Not sure what name exactly to call it but a crab like creature thats reasonably large and more costly than a single arc but way more durable. The crab (creep, lice, crawl or scarab whatever name you like) moves slowly from the hive of its creation, its a large creature with no direct way of attacking however once it burrows into infestation the shell opens up like a clam and spores begin to slowly spread all around it eventually covering a large area, possible for them to spread from 1 room to another if close enough. The spores act exactly like lerk spores and will continue to be released until the creature is either killed or moved by the commander.

Being large and rather tough the crab provides cover for aliens as they progress up corridors. However the crab has 1 major weakness. rooms with power hurt the crab. it dislikes light and will only survive for long periods within rooms with destroyed power nodes.


the purpose of the crab is to either lock down areas you dont want marines entering or to deploy them as close as possible to a marine base and then begin to fill up the part of both the room the crab is in and their command room with spores.


Marines can combat crabs by either sneakily powering up rooms they are in, heavy GL bombardment, firing from a safe position outside the psores range, using exos to progress through the spores or flamethrowers to clear them.