Purulent pericarditis is a rare disease in the era of antibiotics, with Streptococcus pyogenes being a possible, though uncommon etiology. Even more uncommon are mycotic aneurysms secondary to group A strep purulent pericarditis and bacteremia. We report a case of an 18-year-old female with a history of strep pharyngitis develop Streptococcus pyogenes purulent pericarditis with subsequent ventricular fibrillation (VF). Following initial stabilization, she ultimately developed a 4.8 cm mycotic aneurysm of the ascending aorta, with resultant compression of the pulmonary trunk and right pulmonary arteries.