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Koopakids have appeared in every Mario Party game. Koopakids can turn into three different ones (Green K., Red K., and Blue K. Kid), as seen since Mario Party 5. Koopakids are often confused with Bowser Jr., but since Hudson didn't know the names of the seven Koopakids, they just named them Koopakids! They are playable in Mario Party 5 and Mario Party 6, but went back to NPC's in Mario Party 7. There seems to be multiple Koopa Kids, and not just the colored versions.