The Roguelike ''[[VideoGame/AncientDomainsOfMystery ADOM]]'' has some elements of this as well as NetHack.
* For example: The regular use of the blanket is to automatically wrap up objects you are carrying (so a waterproof blanket protects them from rust, a fireproof blanket protects them from melting, etc.) but if you dig a hole in the ground you can put the blanket over it to create your own pit trap.
** Normally, a trap's type is directly determined by its coordinates; at one point, covering a pit with a blanket would turn it into any kind of trap (including fireball, water or teleportation traps) depending on where it is. The bug was fixed for future releases, however.
* If you try and fire a projectile at the spot you're standing in the message, "Try to find a more creative way to commit suicide" appears.
** Similarly, you can use the talk option to talk to yourself by aiming it at your square.
* You know that "Useless Potion" item? Turns out that if you find a use for it, not only does the game commend you for it, it gives you a random artifact as a reward. [[spoiler:It involves propelling yourself by throwing it in the Caverns of Chaos's slippery ice level.]]
* ADOM has lots of these. Among others, attempting to sacrifice yourself while wearing an amulet of life saving, using nearly all abnormal skills (e.g., pick pockets, ventriloquism) on yourself, escaping Arena fights by teleportation, wishing for unusual things (e.g., babes), kicking staircases, etc. will all produce unusual and occasionally unfortunate effects.
* Press & (monster memory) and type in your character's name. Or the Almighty Creator's.
* Stethoscopes can be used on enemies to [[EnemyScan measure various stats]]. This, however, doesn't work on undead and constructs... because they're not ''alive''.
** Applying a stethoscope against a door will give a rough estimate of the amount of monsters in the room.
* Talking to an animal activist ratling while wearing a fur will make him shout "Ye animal ssslayer! Sssuffer!", become hostile, and spray a blinding liquid on your face.
* Equipped inventory interacts logically:
** Rings worn under gloves or gauntlets never get damaged.
** Similarly, rings can't be put on or removed with gauntlets on. Furthermore, items equipped under a cursed one can't be removed: Cursed weapons prevent changing gauntlets, and cursed girdles prevent changing armour.
* Rubbing a ring of djinni summoning causes a djinni to appear next to the player character. This is usually used for receiving a wish, which causes him to disappear instantly when the wish is granted. However, if the player character is completely surrounded by monsters, the djinni will [[OneHitKill instantly kill]] one of them [[TeleFrag to make room for himself]] and then give whatever reward he was supposed to. ''However'', trying to use this technique to insta-kill a boss will [[ContractualBossImmunity make him complain that there's not enough room and refuse to appear]]. Additionally, if used on the level of the BonusBoss, he will look around nervously, gulp, and disappear.
* Choking on your own vomit, by falling asleep when sick.
* Suggestions from the feedback forums often go towards this trope. Actual example: the game could acknowledge you as especially evil if you kill the cute dog, then eat it in front of the little girl it belonged to, and ''then'' eat a rat so that you'll vomit the dog's remains all over her.
* If you are playing an illiterate character and you eat a fortune cookie, your PC is strongly implied to ''eat the fortune'' while it is still inside!
* If you drink from a pool, sometimes a talking frog will pop out. If you're female, he'll send you on a quest. If you are male, he'll say that you are 'of the boring kind'. The frog might explode if you are male and deaf; if this kills you, you get a unique death message.