Take the Dead German Composer Test!Arnold Schoenberg remains one of the most "infamous perpetrators" of modern dissonant music, despite the fact that he's hardly modern anymore based on years alone. Schoenberg was the major innovator of the 12-tone school of atonality, and this alone makes people still fear his work to some degree. Yet he personally was even scarier than his music was--Schoenberg was arrogant and intimidating, an individual who made no effort to be social or kind, and who thus was isolated so seriously that nobody even ever called him by his first name.
A few key works: Verklaerte Nacht, Pierrot Lunaire, various generically-titled chamber works, Pelleas und Melisande
It is kinda me I guess....