The TRAP (reverse arterial perfusion sequence) is a series of complications in monochorionic twin pregnancy in which the affected twin (fetus with cardia) is perfused backwards by the 'pumping' twin through a large arterio-arterial (A-A) and veno-venous (V-V) anastomosis, in which the twin with cardiac arrest is born with a somewhat developed body and limbs, but a partially formed head and face, due to a reduced supply of oxygen and nutrients; with severe malformations, an abnormal lack of development, that in 50% of cases the normal twin dies because of heart failure and prematurity. We present a case of acardio anceps fetus (Das K.1902), female, for the first time for the Department of Sucre, Colombia, S.A.; product of a multiple pregnancy of a mother of 23 years, from Centro Alegre Tuchin, Cordoba, referred by a gynaecological specialist in Asplejo.