If you're looking for more evidence that simply plunging a living being, frog or human, into an already-boiling cauldron will stimulate that creature to bounce out self-protectively, unharmed, consider this recent sad news from Russia:
I will now give this theme a rest again for a while. Really it's my common sense that is offended here, as even trained scientists keep using a boiled-frog metaphor they would realize couldn't possibly be true if they thought about it for one minute. Oh well. On the other hand, I personally believe the moon is made of green cheese.