Here's a fun strain for the boiler, the psychic boiler, it can no longer lob acid globs, instead it can briefly gain control of target marine for 2 seconds. It can then walk behind a marine and fire several rifle rounds in their back but towards the general direction of the xenos, pretending that the marine is just being utterly careless. The goal is to get as many marines salty as possible at other marines for "ruining their round".