Two magic items

Arachnid Servants of Hypnos

Four silver spiders in a velvet bag; when the bag is opened, the spiders swarm forth and envelope up to four willing creatures with their webs.
The cocooned creatures fall asleep for 1 hour. Their dreams are sweet and filled with the sounds of the wind playing the web’s strands as a harp. The creatures are completely unaware of their surroundings and cannot be roused by any means. This 1 hour sleep mechanically counts as a full rest in terms of healing, spell memorization, etc. Furthermore, each affected creature regains 1 HD worth of hit points.
After the 1 hour, the webs dissolve, and the four spiders crawl back into the velvet bag.
However, there is a flat 1-in-6 chance for each affected creature to fall into a week-long coma (and possibly gain a spiderific mutation). Delay Poison grants a save vs. poison to counter this effect.

Soap of Absolute Cleanness

This inconspicuous bar of soap removes all curses, diseases and similar ailments if someone washes themselves with it.
However, each time it also scrubs away one of the seven layers of the skin of the user. Repeated use leads to serious consequences as the person’s skin is eroded. This can only be healed by miracle-level restorative magic. The soap is good for 1d8 uses.

Layers of skin left	Effect
6	No effect yet
5	Can no longer wear armor heavier than leather
4	Can no longer wear any armor, -1 on Reaction and Loyalty rolls
3	Double damage from fire, acid, and similar sources
2	Can no longer wear clothes; skin now almost completely transparent; double damage from any kind of attack
1	Uncle Frank from Hellraiser
0	Death

1d8 spider mutations

From the creative duo that brought you the 1d6 things that happen when you lie to the skeleton interrogator... 1d8 horrible but also kinda useful mutations you can get from being bitten by a giant arachnid!

1. Eyes all over your forehead, unable to concentrate for a week (-2 on all rolls), afterwards 270 degree vision, only surprised on 1 if you can theoretically see it coming.
2. Your teeth fall out, and mandibles burst forth from your mouth. Your bite now does d4 damage, but you cannot eat solid foods.
3. You can cast a 10' x 10' Web once per day, but doing so leaves you exhausted and hungry and you gain 2 points of Encumbrance until you rest and feed. Also, it's a spiderweb, so guess where it shoots out from!
4. A new gland grows in your body and secretes 1 dose of a potent poison per day (effect: save or unable to move for 1d6 rounds). You are NOT immune to this poison. If you don't have the opportunity to drain the gland once per day, then save or be unable to move for 1d6 HOURS. Otherwise, you can use the extracted substance as weapon or food poison. The poison looses potency in 1 hour after coming out of your body.
5. Sticky body hair, can cast Spiderclimb once per day, but handling things is a pain in the ass. Manipulation of objects (including taking clothes or armor off) takes twice as much time, and you are unable to attack on the same round when dropping or swapping weapons (and attack with -2 on the next).
6. 1d3 +1 vestigial legs sprout from your buttocks. They are both gnarly AND useless.
7. According to a collection of 85 fun spider facts, "it is estimated that a human is never more than 10 feet away from a spider—ever". Awareness of this fact renders you unable to sleep peacefully - you need 2 extra hours to rest up properly. Once per week, you can call out to all spiders in the vicinity: a sizable swarm crawls out and fulfills one command.
8. Arachné's blessing. You become incredibly talented at weaving. During downtime you may spend a week to create a tapestry worth 1d6 x 100sp. On 6, roll another mutation.