Billy was about to comment on Ryo's happiness when the Imagin struck---then, suddenly there was a sand-spill, and a presence that definitely wasn't Ryo's. He'd been forewarned about possession, so it wasn't as alarming as it could have been, but he remained on guard.

"Okay," he parrots back. "How should I address you?" Because if he's going to effectively separate the Imagin from Ryo in his mind, he'll need a name. Preferably one that's better than 'lightball'.