Spiked Koopa Is Not A Koopa But A Bros.
So the boss named Spiked Koopa who is a member of the Brown Sugar Pirates is not a actually Koopa, but rather the species Hammer Bros. are a part of.
This is because in Japanese his named does not contain Noko or NokoNoko, but rather is Toge Burosu meaning Spike Bro. Due to his shell being a different model from typical Bros. Shells, he is able to retract inside of it and uses it in boss fights. While some people have suggested turtles like Hammer Bros. are Koopas, it hasn't actually been stated to my knowledge.











