A Mega Urchin (also called a Big Urchin or a Giant Urchin) is a larger variety of the Urchin found in the New Super Mario Bros. series. They behave in the same manner as Urchins, however, they cannot be defeated without a Starman.
History
New Super Mario Bros. series
New Super Mario Bros. Wii
Mega Urchins make their debut in New Super Mario Bros. Wii. In this game, they are commonly found in World 4-3 both lingering underwater and on the water's surface aiming to hit Mario with their pointy bodies. There is no way to defeat a Mega Urchin without a Starman.
New Super Mario Bros. U/New Super Luigi U/New Super Mario Bros. U Deluxe
Although Mega Urchins are absent in New Super Mario Bros. 2, they reappear in New Super Mario Bros. U and New Super Luigi U. In these games, they are far more common appearing frequently in Sparkling Waters. Once again, only the effects of a Starman can destroy them. In this game, the are also seen riding on the Waterspouts, they are also seen guarding Star Coins.
They reappear in New Super Mario Bros. U Deluxe with the same role.
Other appearances
Mario Golf: World Tour
Mega Urchins reappear in Mario Golf: World Tour in the course Cheep Cheep Lagoon, where they appear as obstacles to avoid. They also appear in the background on some other water courses.
Super Smash Bros. for Nintendo 3DS
Mega Urchins also appear as obstacles in the Mushroom Kingdom U stage found in Super Smash Bros. for Nintendo 3DS hurting any players that make contact. They rise on the Waterspouts.
Mario Party 10
While Mega Urchins don't appear in Mario Party 10, a similar variety called the Big Urchin did. They are smaller than a Mega Urchin but larger than a basic Urchin.
Paper Mario: Color Splash
A Mega Urchin is also seen in Paper Mario: Color Splash in the Snifit or Whiffit Game Show. It floats above Mario as he answers the questions, every time Mario gets a wrong answer, the Mega Urchin will lower itself onto Mario's bubble. If Mario gets too many wrong answers, the Mega Urchin will pop his bubble killing him and resulting in a Game Over.