Furizō

Furizō are large mechanical spheres found in Mario's castle in Super Mario Land 2: 6 Golden Coins. They have four constantly-retracting spikes, though this does not affect the area of damage whatsoever. A smaller version called Furiko also exists, and according to artwork comes in a different color. They both move back and forth in a pendulum-like arc to damage the player, and are completely invincible.