Punch him

Jake quickly raised his fist, and before his doppelgänger could move, punched him in the face. To Jake's horror, his fist sunk into the doppelgänger's face. He tried to pull away, but his hand was stuck.

The doppelgänger laughed again, and walked towards Jake. With each step, Jake arm sank deeper into the doppelgänger's flesh. He reached out, and gripped Jake's face, his fingers elongating as they covered Jake's flesh. Jake tried to scream, but his was soon covered by his doppelgänger's body. There was a moment of darkness and silence as Jake's eyes and ears were covered. Jake began to panic when he realised he couldn't breath. Then, his eyes, ears, nose, and mouth cleared.

For a moment, Jake was relieved. He could see himself in the mirror, exactly the same as he had been before. The doppelgänger was gone, hopefully forever. Jake only noticed something was wrong when he tried to step away from the mirror, and leave the room, and found that he couldn't move. Deep laughter echoed around the room, and Jake saw that it came from his own mouth.

"You thought you could get rid of me so easily."

It was Jake's own voice coming from his mouth, but Jake knew that the doppelgänger was controlling him.

"You can't stop me", the doppelgänger said. "I'm in control."

To prove his point, the doppelgänger moves Jake's hand down to grip his cock. Jake felt his cock harden as his fingers curled around it.