From the Super Mario Wiki
Chocolate Island is a mountainous island located in the southeastern part of Dinosaur Land in the game Super Mario World. The island is named after its chocolate-brown coloring. Instead of lava, some levels have boiling hot mud. This is the only known island to be a habitat for the Dino Rhinos and Dino-Torches.
The Boss of Chocolate Island is Wendy O. Koopa.
Part of Chocolate Island is featured in almost all the Mario Kart series. Choco Mountain from Mario Kart 64 and later Mario Kart DS might be part of Chocolate Island. Also, in Super Mario Kart and Mario Kart: Super Circuit, there are two courses called Choco Island 1 and Choco Island 2 respectively.
Names in other languages