Antipope Dioscorus

https://en.wikipedia.org/wiki/Antipope_Dioscorus

Dioscorus (died 14 October 530) was a deacon of the Alexandrian and the Roman church from 506. In a disputed election following the death of Pope Felix IV, the majority of electors picked him to be pope, in spite of Pope Felix's wishes that Boniface II should succeed him. However, Dioscorus died less than a month after the election, allowing Boniface to be consecrated pope and Dioscorus to be branded an antipope.