Pillar

Pillars are large indestructible wooden columns found in Super Mario World. These obstacles appear in #1 Iggy's Castle, the Forest Fortress, and room 1 of Bowser's Castle, usually hidden in floors, ceilings, or walls. They move slowly for several seconds, revealing themselves, before suddenly smashing almost anything on their way. After several seconds later, Pillars move slowly back. If the player reaches the door at the end of rooms with Pillars but does not enter it, the nearby Pillar will appear to be cut off by the wall.

A Pillar appears in the first volume in the Super Mario World arc of the Kodansha-published Super Mario manga. While Mario and Luigi are walking through Iggy Koopa's castle in an open room, Mario looks up and tries warning Luigi of a falling Pillar, but it crushes Luigi. Mario then has to toss a crushed Luigi through a window.