Huge Red Electrokoopa
From the Super Mario Wiki
The Huge Red Electrokoopa, also known as the Giant Koopa, is a large variation of the Red Electrokoopa species derived from Koopa Troopas. Despite its name, it is actually dark green. Like the other Electro-Koopas, it is found at Pinna Park, specifically Episode 5, The Runaway Ferris Wheel. In spite of being an individual large version of an existing enemy and being called a "king" by its Japanese name, it does not technically act as a boss in the game, as it never attacks.
The Huge Red Electrokoopa is the source of the problem in The Runaway Ferris Wheel and sleeps on a metal grate behind the Ferris Wheel. Its electrical discharge makes the ride spin uncontrollably, surprising the visitors at the park. Mario can defeat it by flipping the grate beneath it, causing it to fall in the water, and making a Shine Sprite appear atop the flag on the Ferris Wheel. After the Koopa is defeated, the Ferris Wheel's speed returns to normal.
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