Today's odd idea...fantasy, this time, though I could put a superhero spin on it.

Something fantasy-ish

In reaction to some other post, it occurred to me that turning the hereditary ruler into some short-lived mammal like a mouse or mole would not actually kill him/her but would leave them very likely to be killed, thereby skirting a possible geas against killing the rule.

But at that point I suddenly flashed forward to the part where the heros have found the ruler and transformed them back but too late: the ruler expires of old age, despite the fact that it has only been a few months! So the ruler dies without issue.

Or maybe not...

Suppose that the ruler went ahead and did traditional vole/mouse/hummingbird/whatever things, and bred. This sets the stage for the kind of silliness that can only happen in a fantasy milieu, which is the war of succession between the usurping Duke or whatever, and a family of field mice that the heroes can prove are descended from the ruler.

You have some NPC off trying to turn them into humans, you have a vet of sorts trying to figure out who is the oldest, you have people who quite rightly say, “I'm not going to be ruled by a mouse!” and off we go.