A 35-year-old woman with a pre-existing diagnosis of rheumatic heart disease and mitral stenosis presented this time to us with history of recent worsening of her dyspnea and new onset of fever for past 15 days. On examination, she had features of congestive heart failure in the form of congestive hepatopathy, raised jugular venous pressure, and anasarca. In association, she had a deranged coagulation profile with an international normalized ratio of 3.2 and a decreased platelet count of 44 × 103/μl. On echocardiography, she was found to have calcified a mitral valve with severe mitral stenosis (mitral valve area of 0.8 cm2) (A). It also showed a large ball valve thrombus freely floating in the left atrium (LA) and intermittently approaching the mitral valve orifice. The ball valve thrombus (thin arrow) was prevented from sitting on to the mitral valve orifice by a hockey-shaped anterior mitral leaflet (thick arrow), which pushed it back into the LA repeatedly (B, Online Videos 1 and 2). The patient was planned for an urgent LA clot removal and mitral valve replacement but, while awaiting the surgery she suffered a sudden cardiac arrest from which she could not be revived.