Unibō

Unibō are nearly indestructible spiky round enemies that inhabit flying and swimming areas. They first appeared in Super Mario Land 2: 6 Golden Coins, where they can only be defeated by a Super Star or Koopa Troopa shell. They remain stationary until Mario comes near, at which point they will shake on the spot to make themselves harder to avoid. They reappear in Mario & Wario, redesigned to look more like Urchins and with no visible eyes on the screen. In addition, they come in two varieties: those with blue bodies move vertically, and those with yellow bodies move horizontally. They no longer sleep and are contantly moving around.

The original appearance of Unibō is very similar to both Gordo from the Kirby series and Sea Urchins from The Legend of Zelda series.