Hidden smasher

The hidden smasher is a giant slab of steel hidden in a wall that serves as an obstacle in Super Mario 64 and Super Mario 64 DS. It appears only inside the volcano of Lethal Lava Land, where it falls and tries to crush Mario, Yoshi, Luigi, or Wario when he approaches it, acting similarly to a Thwomp. If he is crushed by the hidden smasher, he loses three wedges of health.