What is the name of catholic belief that concentrated bread and wine truly Body Blood Christ?

The name of the Catholic belief that consecrated bread and wine truly become the Body and Blood of Christ is transubstantiation. This belief is based on the words of Jesus Christ at the Last Supper, when he said, "This is my body," and "This is my blood." Catholics believe that when the priest consecrates the bread and wine during Mass, they are transformed into the Body and Blood of Christ. This transformation is not visible to the eye, but it is believed to occur through the power of God.