Sleep Field

Using this spell creates a magical sleep field that will cause everyone that comes too close to it to fall asleep. However, its use is rather limited. If not cast on a narrow path, the caster's foes can simply walk around it, making the creation of the field rather pointless. Also the field dispells itself after several creatures walking into it.

The spells Sleep and Mass Sleep are much better, since they directly target the foes.

Note that "Energy Field" was originally an umbrella term for all the types of magical fields: Poison Field, Fire Field, Sleep Field and Lightning Field, and the same spell would be used to create any of them. Later (after Ultima IV), different spells were designed for each of the fields, and the previous Lightning Field came to be known simply as Energy Field. However, at times the four spells are still called "energy field spells".