For those who play, in the latest expansion, a new species was introduced.
They're a really cool take on sirens/mermaids.

They have a voluptuous female upper body, but with a slightly creepy, aquatic species face.
They have fins everyhere and an extremely long, spiky tail that seems to be a blend of serpent and eel.
As if that wasn't cool enough, they are also winged (although one could see it as batwing-like sidefins).

True to mythology, they are a mix of demon and mermaid, luring and bewitching sailors with their otherwordly voices.
Some friendly ones can be found in the various underwater dive clubs around the isles.
The rest is either hanging out on the cliffs and rocks near the shore, or flying around like birds.
Yes, you read that right!

Here's some info, sadly you can't see form that one picture how awesome they really are:
https://wow.gamepedia.com/Siren