Trap Door

The Door Mimic is an enemy that appears in The Minish Cap. It resembles a normal dungeon door, but when approached by Link falls down, potentially crushing Link if he doesn't move out of the way quickly enough. They can be destroyed with a variety of weapons, including Bombs.

Quote from The Legend of Zelda: The Minish Cap Door Mimic figurine: "Appears in the Royal Valley & Dark Hyrule Castle. They look like doors, but they're really traps! If you get too close to one, it will fall down on you."

Trivia

 * A unnamed enemy that is similar to the Door Mimic appears in Ocarina of Time in the Fire Temple and the Gerudo Training Ground. If Link tries to open it, it will wobble then fall on him. It can be destroyed using Bombs or the Megaton Hammer. The difference is that Door Mimic will stick out and behind the bars is usually shown as a brick wall.