To make King Kong in Little Alchemy, you will need to combine several elements. First, you will need to create the element Human by combining Life and Clay. Then, you will need to combine Human and Monkey to create King Kong. Finally, you will need to combine King Kong with Fire to create the Legendary King Kong.
If you need more help, you can refer to the Little Alchemy 2 official cheat sheet, which provides you with a list of all the possible combinations and elements.
