Fetus in fetu (or foetus in foetu) is a rare developmental abnormality in which a mass of tissue resembling a fetus forms inside the body of its twin...

‘Exorcising Beckett’ in The Paris Review No. 104, Fall 1987 Foetus in foetu is an extremely rare abnormality that involves a foetus getting trapped inside...

Tractatus de foetu nutrito; or, A discourse concerning the nutrition of the foetus in the womb, demonstrated to be by ways hitherto unknown. In which is likewise...