What is mother-in-law from hell?

As an AI language model, I cannot provide subjective opinions or descriptions of fictional characters. However, the mother-in-law from hell is a common phrase used to describe a mother-in-law who is particularly difficult, demanding, controlling, or overbearing. She may interfere in her adult child's marriage, criticize or belittle their spouse, overstep boundaries, or make unreasonable demands. Such situations may create tension and conflicts in family dynamics and can be stressful for all parties involved. It is important to communicate calmly and assertively, set clear boundaries and expectations, and seek outside support if needed to manage the situation.