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Question: Xenomorph Stalking PCs in Stealth Mode

Posted: Sun 05 Jul 2026, 01:13
by Wuffles666
I understand the Passive Opposed Observation rule for determining the outcome of two parties coming unexpectedly into line of site of each other during Stealth Mode, but haven’t been able to find any rule regarding a xeno stalking an unsuspecting party in Stealth Mode.

Is it safe to assume this would be an Opposed Roll of the xeno’s Active Mobility vs. the PCs’ Passive Observation?

Just picked this game up a week ago (Evolved Edition). Been trying to prepare for a game tomorrow. Thanks in advance.

Re: Question: Xenomorph Stalking PCs in Stealth Mode

Posted: Sun 05 Jul 2026, 01:31
by Fenhorn
You can see the special Xenomorph Combat Rules on page 208. Xenomorphs use Observation when sneaking around just like PC or NPC.

Re: Question: Xenomorph Stalking PCs in Stealth Mode

Posted: Sun 05 Jul 2026, 02:05
by Wuffles666
You can see the special Xenomorph Combat Rules on page 208. Xenomorphs use Observation when sneaking around just like PC or NPC.
Thank you! I will check out the special xeno rules.

Re: Question: Xenomorph Stalking PCs in Stealth Mode

Posted: Sun 05 Jul 2026, 08:02
by _ArthurDallas_
You can see the special Xenomorph Combat Rules on page 208. Xenomorphs use Observation when sneaking around just like PC or NPC.
Thank you! I will check out the special xeno rules.
...

Wuffles666, just to add to Fenhorn's information, when handling opposed rolls for PCs with either an NPC or a Xenomorph, you should always use the same type of skill (observation vs. observation or mobility vs. mobility). Otherwise, it doesn't make sense to compare apples and oranges.

There are exceptions, though. When "grappling" by a Xenomorph, to break free, a PC must perform an opposed roll "Close combat" to get free, but the Xenomorph uses "mobility".

Arthur.

Re: Question: Xenomorph Stalking PCs in Stealth Mode

Posted: Sun 05 Jul 2026, 16:53
by Wuffles666
Thanks you. I did a Google search and it came up with false information, hence my confusion. Observation vs. Observation it is.

Got two and half hours of sleep last night studying rules. Today will be my son's first TTRPG experience. Wish me luck!

Re: Question: Xenomorph Stalking PCs in Stealth Mode

Posted: Sun 05 Jul 2026, 23:11
by _ArthurDallas_
Thanks you. I did a Google search and it came up with false information, hence my confusion. Observation vs. Observation it is.

Got two and half hours of sleep last night studying rules. Today will be my son's first TTRPG experience. Wish me luck!
...

Everything will be fine. One last important point. You have to treat the Xenomorph with a killer instinct. It doesn't give anyone any quarter. However, at the beginning of the gaming session, you can be generous, and luckily, a Xenomorph might get distracted after a few attacks (to scare your PCs, for example, the Xenomorph hears a noise in the distance and quickly leaves). But at the end of the session (the game), you go all out and show no mercy. Always adapt the Xenomorph's signature attack to your game situation (you can change some things; you're the Game Mother).

Good luck,
Arthur.

Re: Question: Xenomorph Stalking PCs in Stealth Mode

Posted: Mon 06 Jul 2026, 05:44
by Wuffles666
Just got back. Everyone loved it. I’m glad because I’m a little sick of running D&D.

Yeah, no worries about the killer instinct. My players know I don’t have any compunctions with killing off their characters. Lots of atmosphere and tension, lots of Stress and Panic—ramping up to the surprise attack and the 11 dice Acid Spray that nearly killed my son’s character. Good times.

Re: Question: Xenomorph Stalking PCs in Stealth Mode

Posted: Wed 08 Jul 2026, 21:43
by _ArthurDallas_
Just got back. Everyone loved it. I’m glad because I’m a little sick of running D&D.

Yeah, no worries about the killer instinct. My players know I don’t have any compunctions with killing off their characters. Lots of atmosphere and tension, lots of Stress and Panic—ramping up to the surprise attack and the 11 dice Acid Spray that nearly killed my son’s character. Good times.
..

Wuffles666, I'm very happy your game went well. Keep us updated on how things go if you want.

Enjoy your games,
Arthur.

Re: Question: Xenomorph Stalking PCs in Stealth Mode

Posted: Thu 30 Jul 2026, 15:11
by Lokaarth
I’ve got questions related to the stealth mechanics in Evolved Edition, especially when it involves xenomorphs. I like the cat-and-mouse mechanics introduced and have mental images of Alien Isolation all over the place. But I feel the xenomorphs are still unforgiving and I’m wondering whether the mice might have any chance.

Roleplay starting situation: a group of humans, including a witty synth (OBS 8), is exploring a building where a drone is present, passive in the beginning.

Example 1: the PCs have been silent so the xeno is still passive. Both come within line of sight of each other in an office. The group won a first passive open opposed OBS roll (p. 56) since they’re using the high stat from the synth for the group (p. 57). They choose to hide in this cluttered area. They’re now out of sight of the passive xeno. On the next stretch, they decide to ambush the xeno when it turns its back on them to leave the office. They need to leave their hiding spot, thus coming into line of sight of the xeno (even though they’re still behind it). They want to execute an ambush, which requires them to "make an opposed OBS roll against all enemies in line of sight" (p. 58).
Question 1: am I correct to assume that PCs willing to get the ambush bonus against an enemy need to win two opposed OBS rolls in a row (unless they ambush directly after the initial OBS roll)? If they fail this second opposed OBS roll, they only get the surprise bonus (p. 59)? They can’t ambush from their hiding spot?

Example 2: the PCs have made noise while searching an office. The xeno is now active and is zeroing in on the group, making noises in the airducts that the PCs hear. They have a couple of seconds to decide what to do. They know if they try to hide now, they can only hope that the GM gives them a stretch plus that the xeno won’t get any success on its 8 OBS dice (chance of success 13%). Instead, they decide to stay standing in the office. They don’t have time pressure, and they can count on the synth to win the passive open opposed OBS roll (chance of success 50%).
Question 2: am I right to assume that the hiding mechanics are basically useless against the xenos and nudge the PCs to either ambush or retreat (i.e. fight or flight but no freeze)?

Besides these mechanical questions, it makes me wonder what the rules try to achieve.
I feel like these rules want the PCs to realize they should stay clear from any xeno but the mechanics de facto encourage them to act aggressively (or flee). Am I missing something?

Re: Question: Xenomorph Stalking PCs in Stealth Mode

Posted: Thu 30 Jul 2026, 21:45
by AITTIAStudio
I’d separate the strict rules question from the table effect you want.

For Q1, my own ruling would be: the first opposed OBS establishes who notices whom in that moment. If the humans then stay hidden and wait for the drone to turn away, I would not call for a second OBS automatically just because they are still in the same cluttered room. I’d call for a new roll only when the fiction changes: they cross open space, make noise, split up, aim bulky weapons, communicate loudly, etc. If they expose themselves to attack, then yes, the bonus should depend on whether they are still genuinely unseen. That keeps the “ambush” from becoming a free button, but also avoids punishing players for choosing a good hiding spot.

For Q2, I don’t think hiding is useless against xenos, but it should rarely be a safe end-state. It works best as a way to buy one decision: get one door open, let someone crawl into a vent, draw the creature to another sound, or decide who sacrifices position. Once the creature is active, I’d run it less like “roll every stretch until it finds them” and more like a pressure clock:
  • Passive: clues, distant movement, the players can still avoid contact.
  • Hunting: sound/heat/motion points the creature toward the zone.
  • Contact: one clear chance to misdirect, barricade, or flee.
  • Attack: if they stayed passive too long, the xeno is now choosing the terms.
That way “freeze” is still a valid horror choice, but it only buys time; it does not solve the scene. The mice have a chance, but only if they use the chance to change the situation.
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Arthur.

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