Sea Urchin

Sea Urchins are spiked animals that appear on coasts. While not actively aggressive, they will block paths to stop Link from passing by and cause damage if Link touches them. In Link's Awakening they appear on Toronbo Shores and can only be passed by pushing them out of the way using the Shield. Once Link has the Sword however, he can destroy them with a single swipe. In Four Swords Adventures however, the four Links cannot push or destroy them with any weapons to hand and they are forced to either simply avoid them, or defeat other enemies in the area in order to make them disappear.

Trivia

 * These foes bear quite the resemblance to Gordo enemies from the Kirby series.