Abstract Intracardiac thrombi are commonly encountered as a complication of a recent myocardial infarction, heart failure, atrial fibrillation, or intracardiac devices. The prevalence of atrial thrombi in the absence of these risk factors is not well‐described, but seems to be low. We present a case of a 51‐year‐old man with a massive mobile thrombus in the right heart extending through the tricuspid valve, diagnosed on echocardiography after presenting with a presyncopal episode.