Flashbomb:

Flashbombs are very useful when several opponents must be faced at once. A flashbomb emits an extremely bright light upon impact, the result of its chemical mixture becoming exposed to air. This flash of light will blind all living beings within several feet of the impact, thereby allowing a resourceful Keeper to escape, or if necessary, even the odds against him. The Journals of Morgan mention that the Undead are vulnerable to flashbombs, although it may take several to dispel an Apparition.