Flaming sphere
From Ardrana
A flaming sphere spell creates a burning globe of fire within 10 yards of the caster. This sphere rolls in whichever direction the wizard points, rolling over barriers less than 4 feet tall, such as furniture, low walls, etc. Flammable substances are set afire by contact with the sphere, and creatures in contact with the globe are also damaged.
The sphere moves as long as the spellcaster actively directs it, and can be extinguished by the same means as any normal fire of its size. The surface of the sphere has a spongy, yielding consistency and so does not cause damage except by its flame. It cannot push unwilling creatures aside or batter down large obstacles.
Note: This version of flaming sphere 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.