What is the name of the person who phases into wolf form?  Answer the above question based on the context below:  Bella, who has just given birth, awakens from her human-to-vampire transformation and is introduced to her daughter Renesmee. The rest of the Cullens and Jacob stay nearby, and when Jacob acts possessively towards Renesmee, Bella learns he has imprinted on her, making her furious until Jacob explains what imprinting is. Meanwhile, Bella's father, Charlie, has been trying to contact the Cullens for updates on Bella's health. Carlisle comes to believe that they have to leave Forks, Washington to protect their identities - especially because of Charlie. Jacob, desperate not to lose Renesmee, visits Charlie and tell him that Bella is alive and well, but had to change in order to get better. Jacob also tells Charlie he doesn't live in the world he thinks he lives in, but says nothing about vampires. He then phases into his wolf form. Charlie then visits the Cullen house and meets Renesmee, believing she is a niece of Edward's whom Bella and Edward adopted. Afterward, the Cullens are able to stay in Forks.
A:
Jacob