Archveult's spell dagger was an evocation spell that sent a ghostly dagger flying at a target to disrupt its bodily functions and any spellcasting. The spell was named for its inventor, the wizard Archveult Tattercloak.
Upon casting Archveult's spell dagger, magical force gathered to form a dagger-like image. This was then hurled at the intended target, provided said target was visible to the caster at some point during the casting. The dagger-image vanished upon striking its victim, causing slight injuries and sending surges of energy through their body, as well as causing any ongoing spellcasting to be disrupted. The target's bodily functions were also affected: the spell could cause nausea, dizziness, and a feeling of weakness in random body parts. Particularly unfortunate victims of Archveult's spell dagger could find themselves unable to gather the will to cast spells for a short duration after being affected. Extremely unfortunate victims fell senseless to the ground in a state of temporary paralysis.
- The spell was known to the archwizard Elminster Aumar. He once tried to trade Archveult's spell dagger to the Turmish wizard Skaera Attulbrae, in return for descriptions of certain spells she had devised on her own.