The incidence of prosthetic valve thrombosis post transcatheter mitral valve replacement remains largely unknown. Although it may occur more frequently than after transcatheter aortic valve replacement, only isolated cases have been reported up to now. This unique large mushroom thrombus post TMVR case is first of its kind reported ever. 3D transesophageal as well as transthoracic echocardiography play very important role in early diagnosis and for treatment decision