Curse of the grinning skull

The Curse of the grinning skull, also known as the everwatching skull, was a harmless illusion spell designed to annoy, unnerve, and intimidate its target.

Effects
When the spell of the curse of the grinning skull was cast, it formed a phantasmal image of a grinding, seemingly human skull with eyes that twinkled with unnerving light. The skull floated over its target's shoulder, staring and reacting to their every action. The illusion was visible to all and actively pestered the target by gazing into their eyes, following their head movements, and occasionally moving its jaws in silent laughter.

The spell was often used to scare, intimidate, and identify individuals in the crowd via a floating skull. Another purpose was to force a wizard to cast spells on the illusionary skull, wasting precious spells. The skull was unaffected by spells that physically harmed targets and reflected dispel magic spells back at the caster. Some spells, however, were able to destroy the everwatching skull. All powerful castings of the anti-magic shell, minor globe of invulnerability, or similarly powerful effects banished the pesky skull.

Components
The curse of the grinning skull required verbal, somatic, and material components to be cast. The material components required were a small piece of human bone and a spark of fire. The spell could affect any creature within. The spell was somewhat dependent on luck and the caster's skills with the Art improved the chances of successful casting. A misfired everwatching skull flickered for a moment at the target's shoulder and disappeared.

History
One notable use of the spell happened in the city of Hill's Edge. A rowdy Zhentarim wizard strolled into a tavern called The Banshee at Bay and demanded the best food and drink from the establishment's Bedine owner. The old veteran's daughter was a talented mage herself and created an illusion of three skulls that her father displayed to the "Lord High-and-Mighty," claiming that the skulls belonged to the fellow Zhenths. The cocky wizard fled in panic. At the same time, an old mage was among the tavern's guests. He wiggled his finger and summoned the everwatching skull that stayed with the Zhent for the day and a night to dissuade the agent of the Black Network from harassing the Banshee further.

Sometime later, Elminster shared the story and the spell with his Oerthan colleague – Mordenkainen, during their first meeting in the home of Ed Greenwood on the world of Earth.