Add the following events on Halloween:

• The normal “midnight” effects should begin at 6 PM.
• Intelligent monsters may generate peaceful and with candy bars, which they will give to you when you chat to them. Or possibly, this only happens with monsters that have “homes” such as shopkeepers, priests, and peaceful Minetown inhabitants. (Not specified what happens if a monster generates with a candy bar, but you save the game and come back to talk to them once it’s no longer Halloween.)
• Other monsters have a higher than normal chance of generating with attack wands.

If you quit while on the Astral Plane, your game creates a special type of bones file which only contains the details of your character and their possessions (minus a real Amulet of Yendor, with a fake one added).

When other players reach Astral, their games can load this file to create an NPC of your character replacing one of the generic player monsters on Astral.