MattyB is an 8 year old (official age not confirmed, being 8 years old is a statement made by Hila) cringetastic rapper, who covers famous songs and has no talent, whatsoever. He is by far the most powerful being in the h3h3 universe, being able to cause Ethan mental pain and hallucinations - something not even possible for Jeff Dunham. He was finally brought down to justice by God, himself, when Ethan prayed at The Wall of Tears.
Matty has a MySpace account. Yes, he's that evil.
MattyB was the only person to cause harm to Ethan only through the power of his videos.