Thyrotoxic periodic paralysis is a rare and dramatic complication of hyperthyroidism. Thyrotoxic periodic paralysis classically presents with proximal lower limb weakness in the setting of hypokalemia and thyrotoxicosis. Thyrotoxic periodic paralysis represents an endocrine emergency with a rapidly ascending paralysis that can result in respiratory insufficiency, cardiac arrhythmias, and death if not accurately and rapidly diagnosed. We report a case of undiagnosed fatal thyrotoxic periodic paralysis presenting to the medical examiner. The diagnosis was made primarily by review of the clinical history.