An artifact, likely named “The Fast [something]”, which grants very fast speed, but also prevents you from eating because fast also means to refrain from eating.

Shock resistance (possibly only extrinsic shock resistance) prevents you from being paralyzed by a ghost’s sudden appearance even if you lack free action, because you are resistant to being (emotionally) shocked by things.

Shock resistance turns ‘!’ at the end of in-game messages into ‘.’.

A small fraction of closets should contain a skeleton.

Add “royal blue” as one of the randomized potion descriptions, for two reasons: 1) so that the monarch of a throne room can be given a royal blue potion as a pun, 2) so that there can be a potion that uses the “blue” color, which currently none do.

Fortune cookies will occasionally generate in gold vaults, containing money-based rumors.

Occasionally when you try to attack a python in melee, you instead swap places with it and get the message: “It slithers around you; S, @ = @, S.” (replacing the @ with the hero’s glyph if they are different). This is a reference to multiple variable assignment in the Python language.

If the hero can be represented by S themselves, the displacement never happens, because S, S = S, S is not syntactically correct in some versions of Python (though it is in current versions).

Rogues wearing the randomized “fencing gloves” should be able to sell items to shopkeepers which they have stolen from somewhere else at full price, as a pun on “fencing” stolen goods.

Red light, a y that has an explosion attack that causes paralysis. This is a reference to red (traffic) lights in real life making you stop.

(There could also be green lights whose explosion gives a temporary speed boost, but since this isn’t harmful to the target it’s a sillier idea.)

Any item can be dipped into a potion of levitation to permanently reduce its weight by 20%. This uses up the potion, and it will only affect the item’s base weight, not the weight of any contents (i.e. a bag of holding thus dipped will weigh 12 + contents instead of 15 + contents). If the object is canceled at a later point, it loses this property and reverts to its normal weight.

The effect cannot be stacked; attempting to dip an already-levitated object into another levitation potion will have no effect and will not use up the potion.

A possible variation is to also confer this effect for potions of enlightenment, since “enlightening” the item could be interpreted as making it physically lighter.

Breaking a wand of wind creates a stinking cloud centered on its space, because it’s “breaking wind”. Possibly only when cursed.

You can affix a ring to a suit of ring mail. This will make it part of the ring mail, and will raise its enchantment by 1 if it’s negative.

Bats flee upstairs whenever possible in Gehennom, because they are bats outta hell.

Vampires can’t step onto sinks, because they “can’t cross running water”.