Suggested by Destroyer Derpy isn’t a big fighter like the Mane 6. In fact you could say that she’s not quite as athletic or fight ready in general because that’s not really her thing. She does her best to help out but against a shapeshifter like Oolong it will not be enough. Oolong is hardly the most powerful DBZ character out there but he can defend himself and attack which is more than I would expect Derpy to pull off here. Derpy will quickly be overwhelmed. Oolong wins.