Edward Payson Evans (1831–1917) collected a number of extremely interesting cases of animal trials and strange legal disputes in his book The Criminal Prosecution And Capital Punishment Of Animals (1906). For example:
Bartholomew Chassenee, a distinguished French jurist of the sixteenth century […], made his reputation at the bar as counsel for some rats, which had been put on trial before the ecclesiastical court of Autun on the charge of having feloniously eaten up and wantonly destroyed the barley-crop of that province. […] In view of the bad repute and notorious guilt of his clients, Chassenee was forced to employ legal shifts and chicane, dilatory pleas and other technical objections. […] He urged, in the first place, that inasmuch as the defendants were dispersed over a large tract of country and dwelt in numerous villages, a single summons was insufficient to notify them all; he succeeded, therefore, in obtaining a second citation, to be published from the pulpits of all the parishes inhabited by the said rats. […] He excused the default or non-appearance of his clients on the ground of the length and difficulty of the journey and the serious perils which attended it, owing to the unwearied vigilance of their mortal enemies, the cats, who watched all their movements, and, with fell intent, lay in wait for them at every corner and passage.
(Pages 18–19)
Another interesting rat-related anecdote:
A faded and somewhat droll survival of excommunication and exorcism is the custom, still prevailing in European countries and some portions of the United States, of serving a writ of ejectment on rats or simply sending them a friendly letter of advice in order to induce them to quit any house, in which their presence is deemed undesirable. Lest the rats should overlook and thus fail to read the epistle, it is rubbed with grease, so as to attract their attention, rolled up and thrust into their holes.
(Page 129)
Similar legal disputes were brought against all sorts of animals including insects:
In the fourteenth century the peasants of the Electorate of Mayence brought a complaint against some Spanish flies, which were accordingly cited to appear at a specified time and answer for their conduct; but “in consideration of their small size and the fact that they had not yet reached their majority,” the judge appointed for them a curator, who “defended them with great dignity”; and, although he was unable to prevent the banishment of his wards, he obtained for them the use of a piece of land, to which they were permitted peaceably to retire.
(Pages 110–111)
Humans have even punished plants:
Among the Kukis, if a man falls from a tree and is killed, it is the sacred duty of the next of kin to fell the tree, and cut it up and scatter the chips abroad. The spirit of the tree was supposed to have caused the mishap, and the blood of the slain was not thought to be thoroughly avenged until the offending object had been effaced from the earth.
(Page 171)
This is a fun aside that caught my eye:
A Frenchman bequeathed his property to his own corpse, in behalf of which his entire estate was to be administered, the income to be expended for the preservation of his mortal remains and the adornment of the magnificent mausoleum in which they were sepulchred.
(Page 110)