Iron bars
Iron bars are a dungeon feature represented by #.
They are never randomly generated, save in SporkHack, and UnNetHack where they might replace doorways. There are iron bars in the Wizard, Tourist and Ranger quests.
You cannot walk through them, and objects thrown through them have a chance of being stopped by the iron bars. Many creatures can pass through them, including xorns, snakes, and yellow and black lights.
In SLASH'EM, iron bars may be found in some of the new levels of Sokoban, and sometimes on maze levels. Creatures cannot pass through the bars in Sokoban; a Doppelganger character may still liquid leap through them, however.
