Dragonbane

Dragonbane
Abjuration
Level Cle 6
Components V, S, M, DF
Casting Time 1 action
Range Close (25ft + 5ft/2 levels)
Area Of Effect 5ft cube/level
Duration 2 rounds/level
Saving Throw Wil neg.
Spell Resistance Yes

This spell prevents any dragon who fails a Will saving throw from entering the area of effect. A dragon can cast spells, blast breath weapons, or hurl missiles into the area of effect. Dragons within the area of effect when the spell is cast are not affected. If such dragons leave the area of effect, they are subject to the spell when they attempt to return.

Material Component: a dragon scale.

This spell was originally from the 2e Tome of Magic