The instrument known for its brass body and played by buzzing lips into a mouthpiece is the trombone. The trombone is a unique brass instrument characterized by its telescoping slide mechanism that changes pitch, contrasting with other brass instruments that use valves. When a musician buzzes their lips into the mouthpiece, the vibrations create sound, which resonates through the instrument's brass tubing. Trombones come in various types, including the alto, tenor, and bass, each producing different tones. They are commonly used in orchestras, jazz bands, and brass ensembles, playing melodies or harmonies and lending a rich, warm sound to musical compositions.