Percy raised Riptide over Jason’s chest.
Panic closed up Piper’s throat. She wanted to attack Percy with her dagger, but she knew that wouldn’t help. Whatever was controlling him had all of Percy’s skill. There was no way she could beat him in combat.
She forced herself to focus. She poured all of her anger into her voice. “Eidolon, stop.”
Percy froze.
“Face me,” Piper ordered.
The son of the sea god turned. His eyes were gold instead of green, his face pale and cruel, not at all like Percy’s.
“You have not chosen,” he said. “So this one will die.”

The Mark of Athena, Chapter XI