Bananas B.

Bananas B is a magical talking monkey who was assigned to be Jake's Animal Guardian when Fu Dog's license expired. At first, he was much better at the job than Fu Dog, but when Chang escaped and came after Jake, he switched sides out of fear for his life. And he would've helped Chang kill Jake if Fu Dog had not arrived to help. Ever since then, he has been Chang's assistant and helped her in whatever evil scheme she does, including the revival of the Dark Dragon.