A 58-year-old female with a past medical history of aortic and mitral valve replacement performed 14 years ago, presented with dyspnea and palpitation. No stroke or embolic event was documented. She was under routine follow up for anticoagulation with effective levels of internal normalized ratio. Transthoracic echocardiography revealed a large freely mobile round mass moving freely in the left atrium (LA), which was partially prolapsing in to the left ventricle (LV) (Video 1). The both mechanical valve prosthesis were normally functioning while the native tricuspid valve was severely regurgitating. As institutional review board approval was not applicable for this report, an informed consent was obtained from the patient and underwent surgical removal via the transseptal approach. The spherical pink colored and smooth surfaced mass seemed as an organized thrombus formed in layers with a viscous central zone with palpation (Figure 1). The tricuspid valve was repaired using the band annuloplasty technique. Histological examination of the mass revealed features consistent with thrombus. Post-operative course was uneventful and patient was discharged on sixth postoperative day.