Any randomly generated large box in the dungeon may become named “Pandora’s Box”. It works like Schroedinger’s Box in that it’s a normal non-artifact box which is never trapped, and the special behavior when it’s opened is to spawn a bunch of nasty monsters around the player and subtract 2 Luck (and interrupt the normal box-opening process). However, there is something good for the player inside.

Wishing for a “mystery box” gives a large box containing 4 (or however many is balanced) completely random items. (Using just a regular mkobj() call; it won’t generate items which are not normally generatable because this is likely to cause bugs.)

Reading create monster while confused has a small chance of creating a trapped large box, which when triggered will say “The box bursts open!” and create monsters like the scroll of the same beatitude would.

New artifact Pandora’s Box, a large box that, whenever it is opened, ungenocides all genocided monsters and spawns one of each genocided species somewhere on the level.

Metal and stone chests can’t be kicked open to break their lock.

It’s harder to force the lock on chests or large boxes made of metal, and increases the chance your weapon breaks. Additionally, the material of the weapon used to force the lock affects the result, if it’s used to pry rather than bash:

• Iron and metal behave as normal.
• Mithril is stronger than iron, and breaks less.
• Copper is slightly weaker than iron, and breaks a little more often.
• Softer metals, such as silver and gold, break less often but tend to bend. A “bent” weapon doesn’t actually become bent internally; it just loses a lot of enchantment.
• Wood is about as good as copper.
• Glass almost always breaks, and can break even if used to bash open a lock.

Pets will never pick up large, bulky containers, like large boxes, chests and ice boxes. For one, picking up a heavy bulky object is unrealistic for many humanoid pets; for another, usually when pets pick up large containers they are doing something annoying like moving around a stash container.

Artifact large box Pandora’s Box: it contains a ton of good loot, but opening it (or destroying it, or tipping it) alters several overarching gameplay mechanics that all make the game tougher.

Since it’s not as straight up beneficial of an artifact as most others, perhaps it shouldn’t count as a generated artifact for gifting/wishing purposes.

Unless you are blind, all boxes are obviously locked or unlocked once you see them. There is no need to first loot a chest only to learn that it’s locked.

You can climb into and hide inside large boxes.

“Coffin” boxes should use corpsenm instead of spe to represent whether they contain a vampire. Useful because it could be used for other creatures (including Schroedinger’s Cat).