Is there an idiom beginning “when a dog is cornered”?

Is there any saying in a complete sentence including “a dog which is cornered”? I have tried to find a complete one, but there seems to be no one.

Actually, what I want to know is how to explain the situation in North Korea. Since I think North Korea has been going through hard times and now they have nothing to lose, they keep threatening with their nuclear weapons as their last resort.

So, I want to use a saying. Is there one like “When a dog is cornered, it bites or attacks or something else?” I want to get a fixed sentence, which is cliché.

If there is another saying that can show the situations above, please give that, too.

Yes.There is a saying which relates to this. Corner a dog in a dead-end street and it will turn and bite

Also,I have read this "back a dog up in the corner it's gonna bite", which means 'If you annoy/irritate something long enough and don't leave an escape route, then they will attack if they feel threatened'

Yes, I've seen the metaphor used. Someone will say: Corner a dog (or an animal, or a snake), and that is when he's most dangerous (or most likely to bite, or most likely to strike) – and the speaker really isn't talking about animal behavior, they are instead describing how people (or nations) can be most dangerous when they feel threatened and cornered.

Here's one example:

He didn't know what to do, but his instincts, his blind rage, the surge of revulsion at what this bully had done, his fear, his pent-up emotions, all spilled over, and he attacked like a cornered animal, gouging, pulling, kicking, punching. (from Bad Intentions: The Mike Tyson Story by Peter Heller, 1995)

Consider, go for broke, stake one's all, and go all in

go for broke

To choose to risk everything; to try to succeed against great odds. We decided to go for broke, and that is exactly how we ended up.

McGraw-Hill's Dictionary of American Slang and Colloquial Expressions

go all in

Games Staking all of one's chips, as in poker.

Putting all of one's available resources into an effort: The governor mounted a halfhearted campaign for the presidency but didn't go all in.

American Heritage® Dictionary of the English Language

Also, have one's back (up) against the wall

have your back against/to the wall

to have very serious problems which limit the ways in which you can act With rising labour costs, industry has its back to the wall. When his back was against the wall he became very aggressive. (Emphasis is mine.)

Cambridge Idioms Dictionary, 2nd ed.