Mega Urchins are enemies in New Super Mario Bros. Wii. They are a larger sub-species of Urchins. Mega Urchins are big Urchins with fat cheeks, HUGE yellow-orange spikes and eyes that are always staring at the player. They only appear in World 4. A Mega Urchin can be considered more dangerous than their smaller sub-species. They float up and down at the surface of the water; their eyes staring at the player. If the player comes in contact with them, he will take damage. Mega Urchins, like any other large enemy, are much harder to avoid than regular Urchins, and jumping over them must be done with caution or the player loses a form or dies at small form. Mega Urchins are nearly invincible enemies. Unlike Urchins, an iceball or fireball does nothing to them. Mega Urchins can only be defeated if touched with the Starman's invincibility.
Mario jumps to/collects the first Star Coin in World 4-3, while a Mega Urchin watches him.
Mario in small form enters the secret pipe in World 4-3 that has the third Star Coin in it. Notice the Coins forming the shape of a heart and the two Mega Urchins watching Mario.
Mario swims under a Mega Urchin in World 4-1, while it watches him. Two Urchins: one asleep and one to the right of a Warp Pipe blowing bubbles can also be seen in the picture.