In terms of the Holy Eucharist, the bread and wine became the consecrated host.
I’m going to assume you were taught what this means when you were catechized.
Did the bread and wine become the literal flesh and blood of Jesus at the Last Supper when Christ instituted it with His disciples and did they eat it as the actual literal flesh and blood as the Catholic church teaches?
Did Christ eat and drink His own body and blood in violation of the OT Law that forbade it?