There was a thread on a D&D forum a while back that had something like this for their Eberron setting. I was thinking with so prevelant a horror setting as Black Crusade can be, what are some good ways we can instill that atmosphere in our players and really bring out the horrors of the warp. I'll start with some that the players might be experiencing soon as they go try to scavenge from the Kasserkratch.

1. The part of the ship that they are in has been long abandoned, and everyone on it killed. The lights flicker, and as they do, it shows the shadows of all the people who worked and lived there. The shadows act, work, play, and react to one another as if still alive, though clearly no one is there. The Heretics can even hear the din of the shadows interaction, people working, arguing, playing, etc.

2. In one of the Reclamation facilities on board the ship, the warband finds some key components to restore the Dark Mechanicus temple that is in disrepair. Through the deck grating, they feel tiny, baby-like hands, grasping at their boots, slowing them down. When they look, there is nothing there but stained grating. Occasionally, they hear the sounds of high pitched giggling.

3. Different bodies that they come across have not been stripped of valuables, and in some cases bedecked in riches far above their station. All of the bodies have been mutilated to cut large grins on their faces (and other locations). Over the Vox-com, they hear low, repeating short stretch of party music. Upon further investigation or movement through the deck, they find a room full of these corpses, propped up around the room, looking at a central table where there are makeshift copies of the Heretics, an untouched, perfectly preserved cake (with lit candles), and wrapped gifts with unknown contents.

Anyone have any good ones?

As the warband explores an abandoned structure (space hulk, station...) they realize that every mirriored surface can transport them into that refection.

4. For a brief moment the lights flick off, allowing a terrifying glimpse of multitudes of horrors beyond the ability of a rational mind to catalogue, staring at the PC's with an unmistakeable hunger. Then the lights come back on, with no evidence of the horrors they just glimpsed.

5. The pc move through a section with a multi-layered deck. The grating they are walking on has large holes and some segments already dropped into the depth below. As the pc cautiously move over the groaning floor, their sight begins to blur for a second or two. As it clears, the whole section looks completely normaly and in a good status of repair. Curses, where have been these holes in the floor?... holes? Why are we talking about holes in the floor? [Willpower Test +20 to resist this illusion of the mind; Intelligence test to remember which sections where complete and stable]

6. The pc find a skeleton with a strange blue-black gem in one of its bone hands. Whenever the pc take up this coin or not, they will later find themselves clutching this gem in their left fist. Just like the skeleton did. They can throw the thing away, it will show up in their hands or their possesion on and on. The only thing to rid of the gem is to trade it for something. The gem brings bad luck and trading it results into 1 point of Corruption (failure). As long as a PC "possesess" the GM, willpower is reduce by 1d5 points. If the GM is thrown away, the attribute damage will return (1 point per hour). After the damage is removed, the gem will return...

7. The pc leave a room through a door which leads into a long corridor. As they all enter the corridor, the door will suddenly close behind them. As they open the door on the other end, they will see a room like the one they once left. In fact, it IS the room they just left and all door lead into the same long corridor where the door closes behind them. But every time, one lit bit in the room changes. First, it is one of the light source illuminating the room that fails. Then, their is a pool of blood in one of the corners. Then, their is a ritual dagger in the middle of the room. If the pc block the door they are leaving through before opening the, the corridor and the room will suddenly become pitch-black and they hear a multitude of voices moaning and growling. But if they open the door at the end of the corridor this time, they will find themselves where it usually would lead.

8. The heretics enter a room that used to be a security station. The room is unlit, except for few security monitors that are still operational after decades of neglect. The screens show empty corridors and rooms, but one of them shows a horrible scene of slaughter. One of the rooms seems to be decorated with the twisted and mangled bodies of all the heretics except one. A shadow, vaguely resembling the remaining heretic flickers across the screen and the screen goes blank.

9. The PC enter a room where one exit (perhaps the only one?) was barriacaded from insight of the current room using an asortment of boxes, furnitur or what-else-is-their. As all PC have entered the room, the barricade suddenly collapses and the boxes/furniture fall down to the ground. The door behind the impromptu barricade just open an inch...

10: As the pc walk on, they recognice that all of them leave bloody footsteps on the floor although the sole of their footware is not stained with blood at all.

11.) TIMETRAP :The Heretics enter a passage wich seems to be made of ancient stones & resembels more of a dungeon passage. Just as they are about to enter into a larger room they trigger the trap and a bunch of frontloader cannons swing into place with the fuses slowly burning giving the players enough time to hit the deck. If they do the whole enviroment will change: There is blood everywhere and legless zombies with warp claws will be attacking them. Let them fight the Zombies for about 4 rounds. As soon as the first one picks themselves up the cannons will just have fired and there is a 75% chance that a cannonball will hit you in the head. Give an opposed roll Dodge. The room will be back to "normal" except that they now see a sign above the cannons which reads: Welcome to the House of Time: There after you could lead em into a medival world where the Heretics could have a slaughterfest. or a mass conversion to Chaos.

12. The PCs find several packing crates filled with what appears to be dust...If they open one, all must make a +10 Toughness check (except one or two random PCs). Any who fail develop itching boils over the next day or two that erupt in tiny crying/screaming/babbling faces when scratched. This does not do much permanent damage, but it is creepy and uncomfortable as hell, perhaps temporarily lowering their Toughness and Perception score. It can also be used to cause (even more) dissension among the group members, as any rivals of the ones who aren't affected could easily jump to the wrong conclusion.

13: As the pc move through an area (it does not matter what this area acutally is as long as it is large) one them recognizes something small falling off them. As the PC looks close s/he recognizes that one of their fingernails just came off. If they stay a little longer another one will notice how one of their teeth comes lose. A little later anotherones nose tip dissolves and digustingly drips down. The PC better leave the area FAST.

14: Every PC that is not passing a hard(-20) test for Willpower our Toughness will experience a strange sensation on the skin of their underarsm. As they begn to check they realize that the sensation is UNDER their skin and it is something moving. Just as they manage to check the bare skin they witness small cuts opening and 1d5+2 centipeds crawling out. [This is just scaring. Thats it. IF you want, you could deal out a point of corruption. Only do so if they have been warned (or had a chance to be warned) that they are entering a tainted area.

15: As they enter a room a strange sensation sweeps over them as they realize they have entered a tainted zone. If they fail a (+0) Willpower test they are confronted by a Phantom Lesser Daemon of the alignment that they are and must fight it. In the case of a Unaligned PC's they will face a Phantom Lesser Daemon of the Alignment that they are highest of. Stats for the Phantom Lesser Daemon are half of the standard statline of that Lesser Daemon as well as the subtraction of all Talents & Traits. The Phantom Lesser Daemon will only attack the PC that caused it to appear in the room. If a PC other then the one that created the Phantom Lesser Daemon attacks a Phantom Lesser Daemon then they will gain 1 corruption (to a max of 1 corruption).

16: Secretly rol 1d5 and add +2. A random PC will suddenly become unable to breath as water form inside his throat (and will pure out of his mouth & nose if he is wise enough to bent over). The PC will be unable to breath for the duration. IMPORTANT: Do not tell the players the duration. Instead, describe to them what happens from turn to turn and watch them act in panic.

Gregorius21778 said:

That would only work on Non-Space Marine PC's as Chao's Marines have the Amphibious trait.

Hpred said:

17: One of the Heretics (GMs choice) starts to hear a multitude of strange whispers. If the Heretic decides not to listen to them the whispers will turn into a choir of scornful remakes fading quickly. If the PC listens to the whispers s/he will find that they hail and adore and praise his/her skills. From now on the Heretic will hear the whispers praising and hailing whenever the PC needs to pass a test. If the test is passed, it will count as having an additional degree of success. But as soon as one test is failed (no matter what) the test will fail with two additional degrees and the Heretic will be stunned for two rounds as the gentle whispers of adornment turn into savage shrieks damning and cursing the PC for his/her inability to master the given task.

If the GM wishes so, the Whispers will simply leave the PC if the next six tests are successfull.

18. The PCs enter a room with several worn-down candles. Upon closer inspection it is revealed that the dripping wax from the candles has formed grotesque faces (possibly the faces of the heretics themselves). If a candle is removed from the room there is a hideous shriek (or laughter) and all the candles go out.

The warband must spread out to obtain and complete several objectives nearly simultaneosly. While seperated, they hear the other heretics nearby, plotting the deaths of the others while seperated. With a proper Awareness test they hear about an ambush or trap set up ahead near the objective. Such a trap is clumsilly set out for the character so that they notice it, fueling the suspicion that something in amiss with their teammates.

Entering a pocket of reality where space is no longer as solid, perhaps giving way to distortion effects or other warping which causes changes in flesh and steel alike. Not mutation but a mere shifting of the natural order of space in an area.

21: While in a certain area, the PC note that their hair and fingernails visibily grow. the effect end as soon as the area is left. Fingernails will break easily (no claws!) and hair will start to lose color.

22. A Rusting affect occurs in an area where bits and piece of weapons and armor fall off , grow metal legs and hands and run around, clinging and climbing all over the heretics to be apart of their person once more. They climb all over their eyes and hands, begging and pleeding, but still fall off and run around.

23. They meet other humans within the warping effect. They people act normally, and are grateful for the assistance, beign desperate for rescue. They look a little odd, though. Their skin texture is like painted wood, and from various points on their bodies there are strings that travel up, but don't seem to have an end, and can't be pulled down.

24: Within a moments notice the room starts to wrap around the pc like it would have been a point cloth that is now wrap around the pc. A few seconds later, the room-unwraps again but the pc are now in a completely different room and feel quit dizzy (perhaps 1d10 temporal Intelligence damage).

25. The players enter a corridor lined with serene looking marble statues, as they advance about halfway down the corridor the power cuts for a moment as the lights flicker back on the players realise to their horror that the statues have all moved and look set to attack, their serene faces warped into viscious snarls. The players better leave before theres another power cut...

26. As the players pass through a corridor they note various windows(viewing ports? on a ship??) dotted down the hall, every time they approach one the lights flicker and for a few moments they hear a terrible scratching. As the lights come on part of a message has been scratched onto the glass... From the outside! The more windows they pass the more complete the message becomes and the more distressed the glass is...
Somthing like:
"You'lll....Seee....Whhat...I...look...like....Whhheeen....The....Glass....Breaks" / "Can...you...breathe...if....one...of... thease...windows...break?"
Que a hasty run to the end of the corridor followed by the sickening sound of shattering glass, decompression and demonic laughter just as they close the door to the corridor behind them.