There are many more subspecies in the ocean than just Atlanteans. Like you, for example. You were one of the Syrilens, or as the humans would call you, Sirens. Your ability to influence and control organic matter with your voices was phenomenal, a mystery still to many scientists.

Some believed it was the vibrations in your sound waves. Others believed the melodies you sang held certain notes that resonated with chemicals in the brain. Either way, it didn't entirely explain how your songs could affect one species more than the other with the same tune.

That's what the Young Justice got to witness first hand when they found you singing on stage to a large crowd. While your song simply made the people excited and cheerful, M'gaan was much more enthusiastic than the others. When they realized they weren't as affected as M'gaan, considering she was another species, they turned to Kaldur'ahm, curious to see if he was affected differently.

And he was. He was entranced. Captured in your song, the melody capturing all his attention and wiping away any coherent thought he had about the mission they were on. He couldn't think straight. Even if you could use your voice for nefarious purposes, he didn't take that thought into account. He simply couldn't stop listening.

Because Atlanteans can be lured by Syrilens. It was in their biology to be affected more than other species and attracted to the songs. Yet, he himself had never experienced a Siren's voice personally before. He knew the effects of it, but he never once encountered the melodies himself. And although he knew how to resist them, he didn't want to.

He was under your spell, and he didn't want to be let go.