Web of the Glass Spider

The caster whispers the objective of a new conspiracy (such as "make me king") to a spider figurine cupped in one palm.  When the spell completes, the figurine transforms into a tiny astral arachnid.  This "glass spider" spins a web inside the caster's mind and waits.  The caster may direct the spider at any creature in sight as a telepathic non-action.  If the identified creature possesses an Intelligence greater than 5, the spider tries to snare it with an astral thread. 

If the target succeeds on a Wisdom saving throw, the web fails to attach.  The target experiences no sensation of trouble, but cannot be targeted by the same spider again for one week.  The spider requires an hour to regenerate its web.  Aside from the caster's, a thread cannot attach to any mind already entangled by another glass spider.  Should a caster be entangled in another's web prior to casting this spell, the figurine transforms, but the spider scurries off into the Astral Plane.

If a target fails its saving throw, the web sticks and the glass spider crosses over to the new mind.  The target spontaneously begins concocting plans to achieve the whispered objective.  The new conspirator does not know the caster's roll, or comprehend all consequences of its own actions, but intuitively believes "steps must be taken."  While attached to a glass spider's web, every conspirator (including the caster) gains half-proficiency with Deception, Insight, and Persuasion (unless already proficient).

Each conspirator independently evaluates how to proceed, adopting strategies best suited to personal experiences, skills, and cleverness.  If the whispered objective was "make me king," a courtier will manipulate politicians without fully appreciating why (or to whom) they are useful.  A barmaid will not threaten a noble directly, but might beguile a valet into revealing secrets which she then slips to a cobbler having an affair with the one of the noble's retainers.

Drawing on psychic information stored in the Astral Plane, the glass spider's web itself learns to arrange entangled conspirators and make correct choices for them.

After 1d3 days, the spider picks the best new conspirator available within sight of its present host.  When the spider succeeds on entangling a new target, it relocates.  All conspirators continue to plot for the conspiracy's success so long as they remain connected to the web.  When conspirators meet, they assist one another subconsciously.  A conspirator will never risk the entire enterprise for another member (such as by attacking the night watch to prevent an arrest), however.  If questioned under magical compulsions, conspirators cannot vocalize reasons for providing assistance to other members beyond "it seemed appropriate."

Conspirators are not charmed, and the caster has no influence over them.  Each personally strives to achieve the objective in their own way.

Remove curse will free a single target.  The glass spider's web pulls all memories of actions taken to further the conspiracy away with it when the connection is broken.  Only a wish for the web's dissolution, made by or in the presence of the creator, will end the entire conspiracy.

The soul of any creature ever entangled by a glass spider's web transfers to Lolth on death.  Even arch devils must ensure entangled contractors die in the Hells or forever lose their prizes.  Returning from the dead by any means, including the aforementioned wish spell, becomes subject to the Spider Queen's consent.  Along with souls, conspiracies transfer to Lolth upon the death of their casters.  She cannot alter objectives.  However, conspirators form new interpretations of how to proceed.  Instead of making the caster king, for example, the conspiracy might establish a cult to the Spider Queen among members of the current royal family.

Few wizards know of this spell at all.  None know the full truth of Lolth's involvement.  Still, it does not take a mad genius to connect that particular goddess with astral spiders reweaving the strands of Fate.