Malevolent is great, but ripples drags that down. Go with vile wake, methinks.The ability itself looks really good.
Work on the drowning aspect? Or the alluring business?
Seems like a good candidate to merge a vampire and a harpy:
Captivating Gaze (Su): A drowned maiden can attract any characterl just by looking onto his or her eyes. This is similar to a gaze attack, except that the maiden must use a standard action, and those merely looking at her are not affected. Anyone the potoplenytsia targets must succeed on a DC X Will save or become captivated. This is a mind-affecting charm effect. A creature that successfully saves cannot be affected again by the same drowned maiden's gaze for 24 hours. The save DC is Charisma-based, and gains a +4 racial bonus against the drowned maiden's killer. The ability has a range of 30 feet.
A captivated victim walks toward the drowned maiden, taking the most direct route available. If the path leads into a dangerous area (through flame, off a cliff, or the like), that creature gets a second saving throw. Captivated creatures can take no actions other than to defend themselves. (Thus, a fighter cannot run away or attack but takes no defensive penalties.) A victim within 5 feet of the drowned maiden stands there and offers no resistance to the monster’s attacks.
Going back to the original text suggests an alluring song, too, so we could do a more direct rip-off of the harpy if you prefer.
Here's my suggested compromise. Give them a big racial bonus on Diplomacy but retain the gaze attack that works only against their killer, or maybe once a day or something.
Ok, I say keep the gaze mostly as written but with some use restrictions. I'll agree to against the killer plus either 1/day or 3/day against all others. And a high Diplomacy bonus when singing? Oooh, maybe they can use a Perform check instead of Diplomacy? Nah, can't see giving them that much Perform.
Cleon, can you agree?

(Dungeons & Dragons)
Rulebook featuring "high magic" options, including a host of new spells.