Cold shatters potions and freezes water. Potions in containers are not affected. Objects in a player's main inventory are not protected by intrinsic cold resistance, but reflection nullifies cold ray attacks. Some melee cold attacks can be protected against with magic cancellation.
Cold can also cause lava to cool and solidify into solid rock. It occurs in NetHack in several places:
- Wands of cold
- Spellbooks of cone of cold
- Frost horn
- Cold resistance
- Valkyries begin the game with cold resistance, and their special spell is cone of cold.
- Brown molds, blue jellies, freezing spheres, ice trolls, ice vortices, winter wolf cubs, winter wolves, white dragons, silver dragons and all liches have cold attacks. Passive cold attacks, used by brown molds and blue jellies, will also add half the damage back to the monster's hit points, increasing the maximum hit point total if the new hit point value exceeds it; if the monster gains enough hit points from this it will divide into two such monsters. You are protected from cold attacks if you have cold resistance.
- You can inflict cold attacks in meleé by wielding the artifact weapon Frost Brand.
- Ice is a terrain feature created by freezing water. It can be walked on but with fumbling effects.
- Corpses on ice rot slower. Rotting is reduced to zero in an ice box
- SLASH'EM features the new role of Ice Mage and the artifact athame named Deep Freeze, which deals cold damage.
- The following new SLASH'EM monsters have cold attacks: snow ants, shadow wolves, mist wolves, steel golems, crystal golems, shadows, and Vecna.
- When entering the Chaotic Quest, you will get the message, "You feel deathly cold."