Visible crew/equipment: When Jeremiah has just stabbed Clarke in the barn, after he goes down the steps and the camera follows him walking away you see the back of one crew member's head and then a second crew member's, starting in the bottom right of the screen. Just before scene cuts to black you see the first crew member turn his head to the left. (00:26:46)
Visible crew/equipment: When Martha and Jonathan are talking about Lionel's job offer in the kitchen, a boom mic can be seen in upper left corner of the screen.
Visible crew/equipment: When Tina, disguised as Lana, throws Pete against the lockers, you can easily see that it's Pete's stunt double.
Answer: No, there is no such character in the comics. He's a "meteor-freak" like all the other baddies on the show. The sound has something to do with him vibrating his vocal cords very fast to create a high-pitched squeal.