Dicephalic parapagus () is a rare form of partial twinning with two heads side by side on one torso. Infants conjoined this way are sometimes called "two-headed babies" in popular media. The condition is also called parapagus dicephalus.If carried to term, most dicephalic twins are stillborn, or die soon after birth. A small number are known to have survived to adulthood.The extent to which limbs and organs are duplicated varies from case to case. One head may be only partially developed (anencephalic), or both may be complete. In some cases, two complete hearts are present as well, which improves their chances of survival. The total number of arms may be two, three or four.Their prospects are best if no attempt is made to separate them, except in cases in which one twin is clearly dying. Terminology
Dicephalus means two-headed. Parapagus means joined side by side.Dicephalic twins are called:

dibrachius if they have two arms altogether (one for each twin),
tribrachius, if they have three arms altogether,
tetrabrachius, if they have four arms altogether,
dipus, if they have two legs altogether (one for each twin). Incidence
Conjoined twins appear in one in 50,000 to one in 100,000 births. Dicephalic twins represent about 11 percent of all conjoined twins. Medical and social response
As late as the 1960s, some medical publications argued that newborn dicephalic twins should not be actively treated or resuscitated. An attempt at surgical separation was reported in a paper published in 1982, but did not result in long-term survival of either twin.
A phytobezoar is a type of bezoar, or trapped mass in the gastrointestinal system, that consists of components of indigestible plant material, such as fibres, skins and seeds. While phytobezoars may be discovered incidentally on barium x-ray or endoscopic testing of the stomach, individuals with phytobezoars may develop symptoms: nausea, vomiting, gastric outlet obstruction, perforation, abdominal pain, and bleeding have been reported. Conditions that lead to decreased motility in the stomach (gastroparesis) and surgeries on the stomach (such as vagotomy or gastric bypass) are associated with the development of phytobezoars. A specific type of phytobezoar, termed a diospyrobezoar, is associated with ingestion of unripe persimmons, which contain a soluble tannin called shibuol that polymerizes into a coagulative cellulose-protein compound in the acid environment of the stomach, to form the bezoar. In addition to their presence in human stomachs, phytobezoars have been documented in the stomachs of slaughtered plant-eating animals. Cause
Gastric phytobezoars are a form of intestinal blockage and are seen in those with poor gastric motility. The preferred treatment of bezoars includes different therapies and/or fragmentation to avoid surgery. Phytobezoars are most common and consist of undigested lignin, cellulose,  tannins, celery, pumpkin skin, grape skins, prunes, raisins, vegetables and fruits. Phytobezoars can form after eating persimmons and pineapples. These are more difficult to treat and are referred to as diospyrobezoars. Phytobezoars are more likely to form due to the ingestion of raw plant foods, even in persons without predisposing factors, as cooking softens them for easier digestion. Treatment
Several treatments for phytobezoars have been described.