Depends on the pope, I guess Formosus was fired in 896:

The Cadaver Synod (also called the Cadaver Trial; Latin: Synodus Horrenda) is the name commonly given to the ecclesiastical trial of Pope Formosus, who had been dead for about seven months, in the Basilica of St. John Lateran. The trial was conducted by Pope Stephen VI, the successor to Formosus’ successor, Pope Boniface VI. Stephen had Formosus’ corpse exhumed and brought to the papal court for judgment. He accused Formosus of perjury, of having acceded to the papacy illegally, and illegally presiding over more than one diocese at the same time.

Eventually, the corpse was found guilty. […] Stephen then cut off the three fingers of the right hand that it had used in life for blessings, next formally invalidating all of Formosus’ acts and ordinations (including his ordination of Stephen VI as bishop of Anagni). The body was finally interred in a graveyard for foreigners, only to be dug up once again, tied to weights, and cast into the Tiber River.

https://en.m.wikipedia.org/wiki/Cadaver_Synod