Purulent pericarditis due toStreptococcus pneumoniae(S. pneumoniae)has been increasingly rare since the advent of antibiotics; however, it still carries a high mortality rate, especially in the setting of tamponade. Bedside transthoracic echocardiogram (TTE) is a useful, cheap, and underutilized tool that can aid in the diagnosis, treatment, and further management of patients presenting to the emergency department with chest pain, as well as during cardiac resuscitation. In this report, we present a case of an acute purulentS. pneumoniaepericarditis of an unknown primary source in a patient coinfected with coronavirus disease 2019 (COVID-19) pneumonia, resulting in cardiac tamponade and cardiac arrest that resolved with the aid of bedside echocardiography-guided pericardiocentesis. We attempt to highlight the importance of clinicians using echocardiography to aid in their clinical decision-making, demonstrating it as a fast and effective tool capable of providing instantaneous feedback.