Every time he spoke it felt...strange...like he'd do whatever he asked of him. But he was aware of it.

"Your voice makes people want to drown themselves?" Arthur asked, then realized who-or rather 'what'-he was speaking to. "Oh, so you're like a syren? Or a mermaid...merman. Or are they all the same thing?"

Up until a few months ago he didn't know either existed out of movies and books and stuff, then he made Phoenix's acquaintance.

"Why didn't your voice lure them scientists into drownin' themselves in your tank?" Maybe he was more susceptible because he weren't as smart as them.