Fog clouds and water and air elementals should be immune to dying from drawbridges. (If the drawbridge is destroyed when they are over the moat, the water elemental should fall into the water but the other two can remain flying.)

If a gremlin steals an intrinsic that is one of the intrinsics monsters can have, they should gain that intrinsic.

Animated topiary, which disguises itself as a hedge (this idea might be best when paired with hedge terrain; #2137) until you approach it and it attacks.

Hermit: an always-generated-peaceful, sessile human monster. Possibly only one can generate per game. He or she collects books and will ask for books when chatted to. In exchange for each book, they dispense a rumor which is false if the book was cursed and true otherwise.

A more complicated extension is that rather than simply taking the books, they could instead stash them into a magic-chest-like extradimensional space, the contents of which show up in an identical chest in the Wizard’s Tower. The significance of this is left up to the player’s interpretation.

Geckos and spiders should be capable of clinging to ceilings, since they can do this in real life. Spiders, in particular, should prefer a strategy of spinning a web and waiting on the nearby ceiling (possibly hiding on the ceiling, though that probably isn’t feasible for giant spiders) rather than roaming around.

While you’re asleep, you should recover HP and energy faster than normal, possibly even at the 1 per turn rate that the extrinsics give you.

Remove scrolls and potions from dragons’ starting inventory, because they are incapable of using them and it’s odd that they get offensive and defensive items they can’t use.

Add a crafting system, but only Cavemen can use it since in real life no one was manufacturing gear and they had to make things themselves. Examples of this include:

• Whittling a quarterstaff or club with a knife creates other wooden weapons, like boomerangs.
• Combining a quarterstaff or spear with an obsidian stone to make a high-damaging obsidian-tipped spear.

If you do not talk to your quest leader by a certain turn count, a peaceful same-role player monster NPC named Chad, Stacey, Kevin, or Jennifer should appear on the quest start level, with the implication that they already did the quest.

• The NPC is equipped with ascension-level gear which includes your role’s quest artifact and a wand of death missing at least one charge.
• When you chat to the NPC, their lines consist of humble-brags and passive aggressive insults about your gear.
• The quest leader’s lines are replaced with glowing praise for the exploits of the NPC.
• They do not have the Bell of Opening; the nemesis still has it. The implication is that the interloper made a backroom deal with the nemesis to make your own game harder.
• The quest leader will allow you to enter the quest to get the Bell, since they are aware it is needed for getting the Amulet of Yendor, but the levels of the quest will not generate any floor objects, while still having all or most of their monsters - the implication being the NPC looted everything already.
• There should be a TDTTOE case for when the hero is already named Chad or Stacey.

Hallucination should block touches of death (via an out-of-body experience) even if it’s being suppressed by wielding Grayswandir.

An artifact, possibly a polearm, which induces (rather than blocks) hallucination while equipped. It should have some unspecified great benefit to using it which makes it worth the hallucination.

If you get seduced while standing on a square that would be dark if not for a light source you are carrying, the foocubus should make the same Charisma-based check to either extinguish it or ask you to.

Add a griffin monster with the following statblock:

• Difficulty 14, base level 11, speed 24, 10 points of natural AC.
• 10 monster magic resistance.
• Neutral aligned.
• Medium sized.
• Has a 2d6 physical claw and a 1d8 physical bite attack.
• Counts as an animal.
• Omnivorous.
• Oviparous.
• Flies, and can be saddled and used as a steed.

Deaths in Goblin Town should produce a bones file, but one that just consists of a partial bones pile (not a full pile; the implication is that the Goblin King removes some of the best items from it) that is supposed to load somewhere in the early regular dungeon as a warning to other adventurers. These piles should contain a corpse, but since the former hero did not die on that space, there is no ghost. The corpse could possibly also uniquely render as “mutilated”.

Fall damage from falling through a trap door or hole should be significantly reduced if you happen to land on grass.

Armor that becomes cursed should have its enchantment effectively reversed; e.g. a piece of armor will still be +3 but it will make armor class worse by 3 points instead of better. If the armor is negatively enchanted, it still makes armor class worse by that amount.

Ideas for a leprechaun race:

• Gets unlimited gold-stealing attacks that allow you to teleport each time you steal gold from a monster’s inventory or beneath their feet, which allows you to set up teleportations in advance by luring a monster onto a pile of gold pieces. Stealing gold gives +1 alignment record.
• Has weak attribute maximums.
• Can enchant any boots to +7.
• Has naturally better AC from being smaller, or instead you sometimes automatically leap and evade in response to an incoming attack.
• Rigid body armor won’t fit because of the small size.
• Luck either starts temporarily at +1 or times out permanently to +1.

If you enter a room containing open pits of lava, print a message “It is hot in here.” If hallucinating, follow this up with “…but it’s a dry heat!”

A monster (imagined exclusively as a pet) that acts like your shadow in lit places, always being right next to you and possibly dying if it can’t be next to you, but if you’re in a dark area it is free to wander off.

Elves can read the runes on any elvish weapons (and probably also the runed wand). This doesn’t have to say anything important, it could just describe the item.

Nazgul can innately see invisible.