Throughout history there have been some strange trials, with unexpected outcomes, and then there's the tale of Pope Formosus. The Pope who never lived to see his trial, but the trial was held none the less.
9th Century Rome was incredibly tumultuous time for anyone sitting on the Papal throne, with most reigns short lived due to the political instability at the time.
Pope Formosus spent his early years in the church as Bishop of Porto in Italy, a post he was assigned by Pope St. Nicholas I. His main charge was to carry out conversion missions across Bulgaria and France. He continued his missions under the reigns of Pope's Adrian II and John VIII, however he soon fell out of favour with John and was excommunicated after fleeing Rome.
He was pardoned 2 years later on the provision that he remained in exile, however when Pope Marinus I came to power, Formosus was restored to Bishop of Porto. Formosus reputation and standing grew and grew over time, and by the time Pope Stephen V died, Formosus was named his successor.
Formosus had grand plans to try and separate the Papal states of Rome from the Roman co-Emperors Guy and Lambert, and convinced the Kingdom of East Franks (modern day Germany) to invade Italy. However before any attack took place, the leader of the Franks seized up with paralysis and had to return home to Germany. Formosus died soon after.
Following the death of Formosus, Pope Boniface VI took his place, however Boniface himself died two weeks into his reign, that led Pope Stephen VI to take the role.
Early into his reign, Stephen (a supporter of Roman co-Emperor Lambert) was not content with the death of Formosus, and with Formosus not being brought to trial (as Stephen had an extreme hatred for the former Pontiff). He ordered that Formosus' dead body be dug up and brought to the Papal council for trial. At the trial they propped his dead lifeless body up on a throne, and even appointed a deacon to answer on behalf of the dead Pope.
The trial found Formosus guilty of perjury and falsely acting as a Bishop when he wasn’t, and his corpse was stripped of all identifying Papal items, and Stephen himself cut off several of Formosus' fingers. He was subsequently buried in a graveyard designated for foreigners, only to be dug up later and cast into the Tiber river.
The incident led to public outcry, and eventually led to an uprising against Stephen, where he was removed and imprisoned, where he was murdered while incarcerated.