Guardian tails appear to be normal animal tails from native creatures such as the desert fox, hyena, or caracul. A thong is attached to one end so that the tail can be attached to a chest, bow case, or quiver.
Once attached, the guardian tail protects the container's contents. The tail instantly knows who the owner of the container is, and protects its contents from being rifled by any except the user.
If the contents are molested, the guardian tail causes the container to polymorph into an animal of the tail's type (the tail now being the tail of the animal). It then runs away or fights if necessary, generally choosing the former over the latter. If it escapes or scares off the intruder, the “animated” container will run and find its owner, at which point the tail and the container revert to original form.
Guardian tails have the following statistics regardless of form: AC 5; HD 2; MV 15; #AT 1; Dmg 1d4; AL N. If slain, the guardian tail and container revert to normal and the tail becomes non-functional for one full day. If the tail is ever cut in two, its magical properties are destroyed.