In the Pen and Pencil Advanced Dungeon and Dragons (PnP, AD&D), there are some spells that did not make their way over to BG, BG2, IWD. Two of these that quickly come to mind are the "Light" and it's inverse, "Darkness" spells.
Cast light spell, and you create light for a set radius. Cast "Darkness", and you eliminate light (rather than create darkness) for a set radius. Certain monsters (Drow, demons) have the innate ability to cast "Darkness", which creates havoc for anyone without infravision, or without "Light" spells. I would have used the "Light" spell when walking around the towns at night. (Casting "Light" while in the open at night would be like placing a beacon for all monsters to find you. )
Any old PnPers out there that can assist me here?