Castle Merciless. Home of He who dwells in nightmares.
Just off the craggy cliffs of Corundum, under the rippling blue ocean waves, seven stones stand. They rise majestically from the ocean floor, references to some long ago civilization. Meaningless, now, to all but the most learned.
There are many scret places in the old forests; the least of which is by no means Old Stone Face
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.