>>45519478Your antagonist should be extremely difficult, if not impossible to kill without massive effort and risk to the party.
The environment the party moves through, be it spess ship, station, or planet should be difficult to navigate in some way for the players. Perhaps spaceships are cramped like giant submarines, where halls are filled with pipes and cables, or hazardous moving machinery, lighting is poor.
You can do weapons one of two ways, either make them risky to use (risk of puncturing the hull, limited ammunition, monsters create hazards when they die, fighting draws more foes, ect) or impotent (monsters are resilient to conventional weapons, situation doesn't offer many potent weapons at all, monsters can only be harmed by very specific kinds of attacks).
Your monster/monsters should represent some deep seated fear or discomfort that most all people can understand. Necromorphs, Zombies, and other collective monsters represent the fear we all have of being forced to join up with groups we don't share anything with, they are the unreasonable mob, the group of others who won't take no for an answer.
Monsters like the Thing or Xenomorphs represent fears of physical violation, they get under your skin and inside you and fuck around in ways you'd rather them not do. They're also the completely unreasonable, either one is a being who's stronger than you, and faster, and they can easily sneak up on you, on top of all that they can't be reasoned with because their minds are so completely alien.
