A small parasite, that can control a marine/dead body and move like a normal player.
attacks:
spy: the alien gets in the back of the marine and lets his teammates know where he is and makes the marine lose hp gradually
cloak:cloaks while he has adrenaline
Control:(2nd hive):Controls marine/dead body(respawnts it)
Isnfect(3rd hive):killso controcled a marine

10 hp 0 armor
Cost: 10 res

Hmmm... Small and cheap. I think it sounds a little overpowered even with the low health. Reanimating corpses could be interesting though.

well it seems good just make it that when it infects are marine it lets that marine know its infected. As a counter make it that a welder can damage it and kill it after a few seconds (giving the alien time to run so its not underpowered).