Trap Door

Ocarina of Time
In The Legend of Zelda: Ocarina of Time, Door Mimics appear in the Fire Temple and the Spirit Temple as an adult. They are just like normal doors but one can distinguish them from normal doors by seeing if the door is bulging out from the wall.

The Minish Cap
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."