Chushan-Rishathaim is a name of a person from a long, long time ago in a place called the Bible. He was a ruler of a group of people called the Mesopotamians who lived very far away from the people who wrote the Bible.
Chushan-Rishathaim didn't like the Israelites, who were a group of people who worshiped God and lived in a place called Canaan. He wanted to rule over the Israelites and make them follow his own rules instead of God's rules.
So, Chushan-Rishathaim gathered up his army of Mesopotamians and attacked the Israelites. The Israelites were very scared because they didn't have a big army to fight back.
But, God was on their side and he sent a man named Othniel to lead the Israelites into battle against Chushan-Rishathaim's army. With God's help, Othniel and the Israelites were able to defeat Chushan-Rishathaim and his army.
So, that's the story of Chushan-Rishathaim, a ruler who tried to make the Israelites follow his own rules, but was defeated by God and the Israelite warrior Othniel.