Applying a pick-axe to iron bars allows you to try to pry them apart, but this has an equal chance of destroying the pick or the bars.

The Iron Ball of Liberation should smash iron bars that it is thrown at or dragged into the square of.

Lightning doesn’t pass through iron bars. Instead, it electrifies the bars and any bars contiguously connected to them (possibly within some range), causing any creature occupying one of the electrified iron bars squares to be zapped as if the lightning ray hit them.

Freeing any hostile monster from a cage of iron bars has a chance of pacifying it.

You can smash apart iron bars by fighting them with a war hammer.

Amorphous monsters that are huge or gigantic cannot squeeze under doors, or through iron bars.

Iron bars can rust by being hit with water or having a water elemental pass through them. Rusty bars are more vulnerable to damage; they can be kicked down and a monk can punch them down. Presumably, non-diggable iron bars cannot be rusted.

When amorphous creatures pass through iron bars, they leave any items they are carrying embedded in the bars. Possibly, small items (as determined by weight) may still able to pass through, subject to a random chance.

The closer someone is to iron bars when attempting to shoot ammo through them, the lower the chance is of it hitting the bars.

Special “cell” room. Only valid if one end of the room has no doors. It generates a line of iron bars across this end of the room, with a locked (iron if possible) door somewhere in the line. Independently, it may contain: a prisoner, a sink, a bed (if those exist), and 1-2 chests with random contents.

Pressure plate traps that cause all the doors of the current room to close and lock (doorways without doors could turn into iron bars or, on deep enough levels, all doors could turn into iron bars). Triggering this automatically removes the trap. Generated very rarely, and has special generation that occasionally makes it appear just inside a door to a throne room.

If you are wearing fencing gloves and are carrying some iron chains, you can create iron bars (a “fence”).

More harassment effects: the chance of respawning the Wizard is a fixed 1/7 and the rest of the effects are equal probability. Multiple non-duplicate effects may happen at the same time.

• Unchanged: curse items, summon nasties, vaguely nervous, aggravate monsters
• Darken much of the level, and extinguish, destroy, or cut the remaining lifetime of light sources. Maybe also blind the player.
• Drop boulders around the upstairs, or iron bars.
• Spawn pools centered on the player, with sea monsters in them.
• Spawn lava around the level, not under the player.
• Create a hole or pit under the player.
• Create a stinking cloud centered on the player.
• If you are carrying the Amulet, it teleports to a random square on your level or the level below.
• If you are carrying the Amulet, it (and possibly any fake Amulets) becomes heavier. This either lasts until the next harassment triggers, or is permanent but the total amount of weight added to the amulet has some sort of cap on it. This is interesting primarily because it targets carry cap, which is a valuable end-game resource.
• A variety of powerful player debuffs such as dealing half damage, taking double damage, blocking HP or Pw regeneration, super hunger, etc.