Amulet of unchanging

Effects
An amulet of unchanging prevents you from changing your current form by polymorph or other means, and also protects you from being slimed; any sliming in progress is halted. It does not prevent you turning to stone.

When eaten, you are "un-changed" to your natural form.

Identification
This amulet is tricky to identify; most situations where you would change form are dangerous.

Strategy
If discovered early, this can be a good substitute for magic resistance in the early game, where polymorph traps are a big threat.