Filverel's doorward

Filverel's Doorward was a spell developed by Filverel Donnathlascen. It was a combination spell, which melded wizard lock with magic missile.

Effects
The spell affected one doorway, hatch, or other entryway protected by some covering, and it affected all coverings on that doorway. When anyone touched the doorway, the spell unleashed a magic missile at them. The guarded surface could do this only once a minute, and was discharged after two such attacks. It did not attack nonliving creatures, nor those protected against spells. dispel magic was effective at breaking this spell; an untriggered doorward could easily endure for centuries.

Components
The spell bore verbal components and somatic components, as well as a very complex series of material components. It required a drop or three of the caster's saliva, and a pinch of dust that had once settled on a potion or some surface that was bearing an active symbol or glyph spell at the time. More importantly, and in a manner unique to this spell, it could only be cast by a mage who was already familiar with magic missile and wizard lock.

History
The spell was developed by Filverel Donnathlascen.