Probably should have asked this sooner but;
So my players are going to start running into Haunts in Mummy's Mask. I think I understand it after seeing some Haunts in Strange Aeons but just 1 question.
Haunts can be noticed during the Surprise round they trigger. Noticed and do..... what? The PC that finds it can warn their allies, can they run away, if they stay do they get a bonus to resisting the incoming effects?
It's really not hinted as to what they can do after noticing espically if doing so takes their standard action during the surprise round, robbing them of their move.
It's all here.
TL;DR: The PCs can warn their allies (probably not useful), run (maybe), prepare to defend themselves (hopefully the notice clue is useful enough to inform the player's action--e.g., noticing the candles in the room flaring up = cast resist fire, notice the empty suits of armor clattering = total defense, what the heck clue = maybe cast something that boosts saving throws) or attempt to neutralize the haunt with positive energy. Occult Adventures adds a great many more things for dealing with haunts, if your campaign includes that material.
Most of the time, none of these things will happen unless you have a high initiative cleric or paladin. That's okay. Haunts are expected to happen--they're story delivery mechanisms above all else. Actually fending them off is a bonus for the players. If a scenario is expected to have a lot of haunts, hopefully the PCs have the opportunity to prepare accordingly--or to bail and come back better equipped for hauntbusting.