Squamous cell carcinoma (SCC) of the lung, a subtype of nonsmall cell lung cancer (NSCLC), uncommonly causes pericardial effusion. Pericardial effusions occur in 10% to 12% of lung cancer cases but are rarely the initial presentation. We report a case of a 68-year-old male with type II diabetes mellitus and chronic obstructive pulmonary disease who presented with right upper quadrant pain, dyspnea, and anorexia, suspicious of hepatobiliary disease. Imaging incidentally revealed a large pericardial effusion causing cardiac tamponade. Cytology of pericardial fluid identified malignancy, and biopsy of a mass found on subsequent chest computerized tomography diagnosed SCC of the lung. The patient experienced respiratory failure accompanied by bilateral pneumothorax, leading to the decision to initiate hospice care. Pericardial effusion warrants prompt echocardiography and pericardiocentesis with cytology. NSCLC-related effusions signify stage IV disease, managed palliatively with immunotherapy and chemotherapy. This case emphasizes the critical importance of evaluating pericardial effusions for malignancy, even in instances where the presentation may be atypical. We present a case of malignant cardiac tamponade that was obscured by underlying hepatobiliary disease. Maintaining a high level of suspicion for malignant effusions is essential, as failure to do so may lead to increased morbidity in patients with undiagnosed malignancies.