Knot-Wing the Koopa

Knot-Wing the Koopa appears as the mid-boss of World 2 in Yoshi's Woolly World. He also reappears in World 4 and World 6. In all three battles, his primary attacks are Ground Pounding and dashing inside his Koopa Shell. Yoshi can defeat Knot-Wing by tongue-grabbing the knot on his neck at the right time when he is on the ground, while he is performing his Ground Pound attacks. After doing so, Knot-Wing will flip over onto his back, exposing the bandages on his underside, allowing Yoshi to attack him with a Ground Pound. All three boss battles with Knot-Wing are replayable in the Boss Tent.

Trivia

 * Knot-Wing the Koopa may be a reference to Hookbill the Koopa due to having similar names and being giant Koopas.
 * This also marks the first time the same enemy (a Koopa Troopa in this case) is transformed twice by Kamek in the Yoshi series.
 * Knot-Wing is the only Koopa Paratroopa that can regain his wings after losing them.