"You shall not make for yourself a carved image—any likeness of anything that is in heaven above, or that is in the earth beneath, or that is in the water under the earth; you shall not bow down to them nor serve them. For I, the Lord your God, am a jealous God, visiting the iniquity of the fathers upon the children to the third and fourth generations of those who hate Me." (Exodus 20:4-5)
"who exchanged the truth of God for the lie, and worshiped and served the creature rather than the Creator, who is blessed forever. Amen." (Romans 1:25)
There is no reason to believe that God would contradict Himself by becoming the very appearance of material objects (such as bread and wine) that He forbade us to worship. The notion of transubstantiation is a clever yet diabolical manipulation of logic. Unfortunately, Catholics are instructed to worship bread and wine on a weekly basis (although they would obviously deny this).