A condition in which a body structure deviates from its normal form because of abnormal development, which may arise from genetic factors or environmental influences during pregnancy.
In mammal births, a round lump of flesh covered in skin and fur sometimes appears, called 'amorphous globosus.' It is a twin that failed to develop and survives by parasitizing the other's blood. In cattle, it occurs about once in every 3,500 pregnancies.