Arm 5

He fought back against the people keeping him there. But he lost control. He didn't own the arms, he was a slave to them, a host. A victim of their unpredictability.

...

The magical blue matter they had offered him made him feel like he was being baptized. He was in control now. Every arm sang along with his soul. They moved like water at a single thought. He could feel the texture of reality through them. Whatever had been moving them before was either dead, or had fled in fear at the blue-green that now filled him.