In the Fief of Huiuspostsebi ruled by a Magocracy, a character must undergo a Trial by combat.
He has been framed by A magic item - sword, relic, wondrous item - and if found guilty of Spying, his punishment will be Baleful Polymorph. The prisoner permanently changes into a small animal. One of my favourite D&D modules is Castle Amber. Wouldn’t it be a neat twist for the central garden to be the prison of several banished beings changed into the form of small animals? If the subjects fail their second saving throw, they even gain animal intelligence, in effect becoming just another creature in the garden.

Fief - Land or office granted to a vassal. Ownership is technically still with the granting lord, but revenue and production is given to the vassal. The lord technically retained the right to seize the land in case of disloyalty.
Magocracy - Magicians who were credited with great power often became chiefs and kings in early societies. A magocracy is a form of government in which society is ruled by such magi, wizards, or witches. The term is used in the Dungeons & Dragons role-playing game and other works, by analogy with aristocracy, meritocracy, and theocracy.
Trial by combat - Fight to the death, winner is innocent