Sentry spheres are usually composed of copper or bronze, and are roughly the size of a softball. Within, four magic spirits are bound, each knowing the following spells: Fly, Telepathy, Project Sight, Resist Magic, Resist Damage, and the attack spell of your choice (Evoke Lightning is fairly common). Normally, one spirit maintains telepathy between all the spirits, another maintains the projected sight, and the third maintains fly. The final spirit directs the other three, and casts attack magic, as needed. One or another spirit maintains the Resist spells, for defense.

Sentry spheres patrol areas, looking for intruders, or accompany a sorcerer as bodyguards. A sorcerer with a swarm of these spheres in attendance is something to be reckoned with...