There should be a way to tell what the acquired resistances of a monster are. This could be by zapping a wand of probing at it, by breaking a potion of enlightenment on it, feedback gained from a stethoscope, or (less likely) a new spell exclusively for pet diagnostics.

Note that it may not be considered “fair” for any of these methods to work on pets, but not work to tell the player’s resistances when they do it to themselves.

Engraving with a wand of probing should produce the same “You probe beneath the floor” effect that you get when zapping probing at the floor, and should likewise automatically identify the wand.

Zapping a wand of probing at a wall point-blank will inform you if there is any open space (walkable terrain, ignoring monsters/objects) between you and the edge of the screen in that direction. This can be used to find vaults and closets.

Monsters can zap a wand of probing at you, which inflicts the studied debuff on you.

Merge the wand of enlightenment into the wand of probing: probing gives enlightenment when zapped at yourself.

Spell of probing, in the divination school, that probes monsters based on skill:

• Unskilled limits it to touch range and gives minimal information on the monster’s status, possibly only showing HP like a stethoscope.
• Basic is still touch range but gives the usual amount of information.
• Skilled shoots a probing beam and gives some additional information.
• Expert allows you to select any space or monster in your line of sight within a radius, and gives the same information as Skilled.

The wand of probing is raised to be on par with the Skilled effects.