Prometheus was a Greek Titan. Possibly one of the most important Titans, as he stole fire from Zeus and gave it to the humans. This system was developed to resist those forces through technological means.
In the middle of an unimportant combat with some bandits a burst of wild magic transforms all of the PCs and their opponents in to random animals and monsters. They retain their intelligence (though not, of course, the ability of speech). They can either carry on the combat in their new forms, panic, or otherwise react how they see best. After about an hour, they return, unharmed, to their normal form.