While walking through the mountains, emerging from several small crevasse near you and begin attacking the party member with the most exposed skin. The Beez are creatures the size of a fist, with minimal stats but high agility. There is ten or more beez. Their sting causes a immediate loss of hitpoints.
As population increases, animal souls are promoted to human before they are spiritually advanced enough in terms of impulse control, etc.: this shouldn't have happened, but karmic progression is automatic, after all--it's a force of nature. But the 'animalization' of humankind bodes ill for civilization.
No doubt the same goes for elves, dwarves, and so on.