Cooligan

Cooligans are species of Penguins and are enemies who first appeared in the game New Super Mario Bros. Wii. They are blue penguin-like creatures that sport a pair of sunglasses. Their name is a portmanteau of "cool", and "hooligan".

New Super Mario Bros. Wii
These enemies first appear in World 3-1, and appear in ice levels. They are seen sliding and can damage Mario and the others if they run into one of them, although if Mario or anyone else is in the Penguin Suit and they are sliding too, then they will bounce off unhurt. It takes two jumps to defeat one. One jump will knock off a Cooligan's shades, slowing it down. They will also fall down holes rather than hover over them. In this state, if rammed by another Cooligan, they will be defeated.

These creatures can be defeated instantly by a Fire Flower, Star, Ice Flower, Penguin Suit, or Ground Pound. Cooligans continue to slide even if they are frozen, allowing the heroes to use them as platforms to reach Star Coins and other objects. They reappear in World 9-5.

New Super Mario Bros. U
Cooligans return in Wii U title, New Super Mario Bros. U. These enemies are first found in the icy world of Frosted Glacier. They behave in a similar manner as in New Super Mario Bros. Wii. They also appear as the Frosted Glacier Enemy Course. Cooligans can be eaten by Baby Yoshis in said game, and even trapped in bubbles blown by them.

Mario Party 9
Snowmobiles that resembles Cooligans make an appearance in Mob Sleds, from the Wii game, Mario Party 9. They are piloted by the three players as they attempt to eliminate the solo player.

Paper Mario: Sticker Star
Cooligans appear in Snow Rise and Ice Flow courses of World 4 in Paper Mario: Sticker Star, where they are seen sliding down from the slopes and wabble through the icy path. Mario can not face Cooligans in battle, but will receive damage if crashes into them.

Mario can jump on a sliding Cooligan to make it disappear instantly. In the Snow Rise level, once Mario uses the Heater sticker, 3 Cooligans can be seen stuck, showing that they cannot slide without ice, and will hop if Mario uses his hammer near them. In the Ice Flow level, sometimes a Curling Stone or another thing will slide down the ice trail along with the Cooligans.

Trivia

 * The Cooligan's attack pattern is notably similar to another penguin-based enemy, the Lemguin.