# Ring of protection from shape changers

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Name

protection from shape changers

Appearance

random

Base price

100 zm

Weight

3

Probability out of rings

3.57%

Probability out of items in:

containers

Rogue level

Gehennom

Elsewhere

0.179%

0.179%

0.286%

0.107%

A ring of protection from shape changers is a type of ring that appears in NetHack.

Contents

1 Generation
2 Description
3 Strategy

3.1 Identification

4 History
5 Messages
6 Variants

6.1 SLASH'EM

7 References

Generation
Wizards may have a ring of protection from shape changers as one of the two random rings in their starting inventory.[1]

Description
Wearing a ring of protection from shape changers causes most shape changers and other similar monsters to lose their shifting ability:

Chameleons, doppelgangers, sandestins and vampires will appear in their base form; they are vulnerable to being polymorphed completely into another monster, and may suffer system shock as with polymorphing other monsters.
Werecreatures will similarly appear in their human form a majority of the time, and are still capable of shifting to animal form, but will shift back to human form on their next turn[2][3] - they also cannot summon help or infect you with lycanthropy.[4][5][6]
Mimics are de-cloaked and cannot disguise themselves.
Monsters with a digestion attack will not polymorph when swallowing a shape changer whole.
Eating the ring has a 1⁄3 chance of conveying protection from shape changers as an intrinsic.

Strategy
An early ring of protection from shape changers can be valuable against werecreatures: though they can still assume their animal forms, they are reliably prevented from infecting you or summoning help and possibly surrounding you, which can be especially dangerous with werewolves. The ring will also reliably prevent other shape changers from chameleons and doppelgangers from shifting, which prevents them taking on out-of-depth forms like the arch-lich that can end your game in an instant.
Pet keepers may be particularly interested in this ring: pet vampires have a tendency to shift to vampire bat or fog cloud form and drop any armor and other items you have given them, and vampire lords can break torso armor by shapeshifting into wolves. The ring of protection from shape changers will keep them in their humanoid form, which is also their best one for combat before factoring in armor, though they cannot revive from their other forms if killed. Pets with digestion attacks such as purple worms will also not polymorph if they swallow a chameleon or doppelganger whole while you are wearing the ring (though they will still polymorph from eating their corpses).
A Rogue embarking on their Quest will likely want an identified ring to trivialize hunting down the many chameleons on each floor.

Identification
Main article: Price identification
A non-cursed 100zm ring can be identified as protection from shape changers by wearing it around known shapeshifters such as mimics, e.g. in a shop or on the top level of Sokoban - the ring will uncloak the mimics immediately.

History
The ring of protection from shape-changers appears in Hack for PDP-11, a variant of Jay Fenlason's Hack, and is included in the initial item list for Hack 1.0.

Messages
The sink looks nothing like a fountain.
You dropped a ring of protection from shape changers into a sink.
Variants
SLASH'EM
In SLASH'EM, changes to polymorph mechanics and the introduction of new werecreatures make the ring of protection from shape changers much more valuable. Shapeshifted monsters that are killed return to their base form, and both werecreatures and other shape changers like chameleons are wont to shapeshifter again before you can kill them in their base form - the ring stops them from changing shape and ensures that killing them will stick.

References

↑ src/u_init.c in NetHack 3.6.7, line 165

↑ src/mhitu.c in NetHack 3.6.7, line 600: chance of changing to animal form when attacking

↑ src/were.c in NetHack 3.6.7, line 38: changing back to human form always occurs if protection from shape changers is active

↑ src/were.c in NetHack 3.6.7, line 137: summoning help checks for protection from shape changers

↑ src/mhitu.c in NetHack 3.6.7, line 600: chance of changing to animal form when attacking

↑ src/mhitu.c in NetHack 3.6.7, line 1310: lycanthropy cannot occur with with protection from shape changers active