From the Super Mario Wiki
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".
Super Mario series
New Super Mario Bros. Wii
These enemies first appear in World 3-1, and later appear in World 9-5. 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 bounce off unhurt. It takes two jumps to defeat one; one jump knocks off a Cooligan's sunglasses first, slowing it down. They also fall down holes rather than hover over them. In this state, if rammed by another Cooligan, they defeat each other.
New Super Mario Bros. U
Cooligans return in New Super Mario Bros. U, first found in Frosted Glacier, specifically in Cooligan Fields. 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 this game, and also trapped in bubbles blown by a Bubble Baby Yoshi.
Mario Party 9
Paper Mario: Sticker Star
In Paper Mario: Sticker Star, Cooligans appear in the Snow Rise and Ice Flow levels of World 4. In the former level, they are seen sliding down a snow-covered slope. In the latter level, Cooligans are seen waddling down the ice path before sliding; this is the first instance in which Cooligans are shown walking. Mario can not face Cooligans in battle, but will receive damage if he 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, three Cooligans can be seen stuck, showing that they cannot slide without ice, and hop if Mario uses his hammer near them. In the Ice Flow level, sometimes a Curling Stone, Rubber Ducky or Cat-o-Luck (Things) slide down the ice trail along with the Cooligans.
Names in other languages