Wall of fire

The wall of fire spell brings forth an immobile, blazing curtain of magical fire of shimmering color -- violet or reddish blue. The spell creates either an opaque sheet of flame or a ring, but in either form the wall of fire is 20 feet high.

The wall of fire must be cast so that it is vertical with respect to the caster. One side of the wall, selected by the caster, sends forth waves of heat. In addition, the wall inflicts damage upon any creature passing through it. The wall of fire lasts as long as the wizard concentrates on maintaining it.

Note: This version of wall of fire originally appeared in the 2nd Edition Player's Handbook for Advanced Dungeons & Dragons from TSR. Its use here is for the purposes of providing context for the campaign only.