Point of care ultrasound (POCUS) is a reliable diagnostic tool for the evaluation of a patient with dyspnea. This case provides an example of an acutely dyspneic patient in which standard evaluation failed to elucidate the true etiology of the patient's dyspnea. The patient was initially diagnosed with pneumonia but returned to the emergency department with acute worsening of his symptoms despite empiric antibiotics leading to the presumption of antibiotic failure. POCUS revealed a large pericardial effusion requiring pericardiocentesis ultimately leading to the accurate diagnosis. This case highlights the importance of POCUS in evaluating patients with shortness of breath.