Continuity mistake: While Earl is in the hospital bed, his grip on the microphone to the waiting room changes from up to down and back. (00:17:55)
Continuity mistake: For several shots during the early scene with the baby in the crib, the blanket changes back and forth from tucked up to the chin, up to the shoulders, and up to the stomach in different angles. (00:01:55)
Continuity mistake: At the beginning, as the mother tucks the blanket up to the child's neck, she changes from both hands on the infant to one hand on the crib. (00:01:55)
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.