Fight him

Jake knew that he had to fight his doppelgänger inside his mind so that he could control him completely. He focused all of his willpower on breaking free.

Instantly, the doppelgänger changed Jake's facial expression so that it showed anger instead of contempt. Jake felt the **** of his doppelgänger's mind pressing against his own. The doppelgänger was much stronger than he was. Jake tried to reason with the doppelgänger, but the doppelgänger didn't even take notice of Jake's feeble attempts. It was more than that. Jake could somehow tell that the doppelgänger enjoyed crushing his mind.

Jake felt his mind get weaker and weaker. Soon, he had no power to contest the doppelgänger, but the doppelgänger didn't stop. He tied up Jake's mind with black ropes that constricted against Jake's mind whenever he tried to think.

The doppelgänger looked at the mirror, admiring his new physical form. For all intents and purposes, he was Jake now, as the pathetic excuse of his old self wouldn't be able to fight back for a long time, if he ever got free. The new Jake turned and walked through the door, ready to start his new life.