TomeNET

(5.20) Wraithform                                                               
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Wraithform, or "pass wall" form is a character state obtained by spell or item:
-Spectral weapons ('A' to activate one for temporary wraithform).
-Ethereal Dragon Scale Mail (just wear it and you obtain wraithform permanently
 until you take it off again).
-The artifact 'Spectral Shard' ('A' to activate it for temporary wraithform).
-Wraithform spell (Udun school)
-Wraithstep spell (Unlife school)

Items that permanently give you wraithform tell you on inspection:
 "It renders you incorporeal").

There is a confirmation message when using the Wraithform spell:
"You turn into a wraith!"       when you attain wraithform.
"You lose your wraith powers."  when your wraithform spell runs out or
                                when your environment hinders your wraithform
                                powers!
The latter happens in those types of vaults that prevent teleportation and can
be very dangerous, as you might find yourself suddenly stuck and unable to
escape quickly, if at all..

Wraithform is very powerful since it allows you to move around the dungeon
without having to follow its room/passages structure, making it easy to pick
encounters or loot items you detected on the ground via detection magic,
and to escape dangerous situations easily (just retreat into walls).

but at the same time wraithform prevents you from attacking anything else in
close combat, except if the target is also able to pass walls (ie possesses
wraithform too, or is actually a ghost or other monster that can pass through
walls).
For this reason it can be dangerous for melee classes to go AFK while in
wraithform, because you will no longer melee-auto-retaliate against most kind
of attackers..

Last but not least, spells cast while in wraithform will only deal half as much
damage as usual, even if the target is in wraithform too.