Bulbul

The Bulbul is a large bulbous enemy with four red, pointy legs and a tiny horned head found exclusively in Four Swords. Its spine is visible through its gelatinous center. Multiple players must slash it back and forth, whittling down its slimy center until its weak point can be hit, destroying it.

Trivia
This enemy seems to be the only reference to Sonic series hidden in the Zelda series: in Sonic Adventure for the Sega Dreamcast, a much similar enemy appears in the Twinkle Park stage.