You reach a chamber with an intact ceiling, lit by ancient glowstones embedded into the walls. As you enter, stone doors slam shut behind you, and something terrible begins to rise…
The PCs are attacked by an undead guardian within an ancient dungeon.
If you're running The Icon Curse Quick Adventure, the statue the PCs are carrying should scream before the doors slam shut, as it is unwilling to return quietly to its seal.
This is a battle to the death; defeated PCs can spend 1 Karma at the start of their turns to regain 1/3 of their max HP, rounded up (and can take their full turn).
Battle occurs in a lit, sealed ritual chamber (O) with two small shadowy rooms off to the west and east (S, W) and a pair of elevated platforms (F) on the north side.
The west room (S) has a cracked wall from which the Mindfang Spiders emerge. A new one will enter the scenario at the end of every odd-numbered round (and one starts there at the beginning of the scenario). There's loose rubble above the crack; a PC can play a ranged or reach attack (vs. Miss 1d4) to knock it over, sealing the crack and preventing any further Spider arrival. Because of the lighting conditions, a PC will need to illuminate the room to see what's going on (you may also require the player to ask questions or investigate before revealing the rubble, but only if this is typical for your play style; don't spring this on players that have no expectation that this is needed in combat).
The east room (W) has sanctified waters that still remain; as a Strategy, a PC may drink to gain +1 Resilience and Unholy Resistance 1 until the end of the scenario. This may be done repeatedly, though only the Resilience bonus stacks.
In the north, there are elevated ceremonial tables (F) each with a jar of Purifying Flame. The old stone stairs reaching them are mostly gone; a PC will have to either climb (Height 1, Acrobatics vs. 1d8) or hop up and across the gaps in the stairs (Height 1, Acrobatics vs. 1d6) from within those sections to reach the tables. The remaining platforms are too narrow to fight on, however; attacks cannot be played from there, and if an occupying entity suffers damage, they fall (this does not apply to entities with Height 1, such as the spiders).
Because these are two individual jars, they are one-time use (rather than one use per scenario). The PCs don't have to use them here, but once they're used, they're gone. The jars they're kept in are fine relics; unused Purifying Flame jars may be each be treated as a Valuable.
F F O ^ S O O W N P
The undead are mindless aggressors and will simply attack the nearest PC. They leave the spiders alone.
The spiders are more intelligent, though their tactical options are quite limited. They're drawn to Incantations and will do what they can to Devour Thoughts of those capable of chanting them.
Destroying the undead dispels the curse and opens the doors, allowing the PCs to proceed. If you have 5+ players, offer an additional Valuable reward, perhaps in the form of a gem-studded box holding naught but ash.
The PCs are killed, ending the adventure.
If you're not using this scenario as the big end to your dungeon or adventure, you may not want to make it to the death. Have only the far exit seal shut so that the PCs may flee in the case of defeat, suffering an Injury instead. In this case, if the PCs had sealed the opening before leaving, you might have the Spiders clear the rubble while the PCs run and nurse their wounds. In this case, they'll need a new plan for sealing the crack, or you could simply have Spiders stop appearing once the undead are defeated. Any undead that were previously defeated rise again.
Or, with higher PC counts, you may want to make the opening tougher to seal. Instead of rubble above the crack, place a boulder or some ancient stone furniture next to it. Two PCs must work together, each spending an Action within the same round, to move the obstruction over the crack. If either PC suffers damage after spending the Action, the effort is canceled for the round. You might also permit a difficult Acrobatics roll to do something fancy to move the boulder; if a PC comes up with a suitable idea, permit it against 2d6.