Thank you for the good questions, I'll do my best to help explain the Catholic viewpoint.
The idea that a priest is able to command Jesus to descend from His Throne in Heaven, and duly command him to be Incarnated, (and in bread, at that), seems like blasphemy.
You are right that it would be arrogant for a priest to presume to order Christ down. Actually, we believe that Christ himself acts in the priest to accomplish his own priestly duty. This action is called in persona Christi. Secondly, Christ himself commanded the disciples to do this in memorial of me, a New Covenant in His Own Body and Blood replacing the old Passover order.
- In the Old Testament, the requirements for the Passover meal involved the sacrifice of the lamb, spreading of blood, and consumption of the lamb.
- In the New Testament, Christ is the lamb himself, shed his blood on Calvary and now invites us to his feast, to receive himself ( cf. 1 Corinthians 5:7-8).
Jesus is very clear that the next time He is physically present on Earth, every human eye will see Him in His Bodily Figure.
- Why would he be physically and literally appearing under the appearance of bread in a thousand places every day?
Jesus said in John 6:40,
This is the will of my Father, that everyone who sees the Son and believes in Him may have eternal life, and I will raise him up on the last day.
- Have you seen him?
- And believed?
Catholics fulfill this every time the Sacred Host of Christ's precious Body is elevated, though only the eyes of faith see. In this dialogue, Jesus was pointing to Himself in the Resurrection, transcendent of this earthly limitation. That is why the listeners got confused, failed to trust, and then abandoned Him. He will come again in a way that will leave no room for doubt, but then it will be too late; the time for faith and trust is now. He is in a thousand places everyday because he is Lord of all and is everywhere. (Malachi 1:11) He is not divided up but rather one bread that we share, meaning One Lord, who sits outside of time and space as we know it.
Try this exercise: Draw a line. Now put points on the line. Protestants think of the Catholic Mass like that, a repeat, each one a new event, each separate from the other. Time is viewed linearly.
Now draw a circle and put a dot in the center. Now connect every point on the circle you could possibly make to the center by means of a spoke. That is the Mass, the Eucharist, the Sacred Bread. It is the same in all time, in all places, because it looks through a window of time and space as we understand to the one reality of the transcendent one.
It's like a time machine making us present to Calvary, the Last Supper and all of Christ's salvific work it at the same moment. We may be divided by space and time, but he is not — when we are in Him, we all become one; thus this is our communion bread.
When we literally consume the Eucharistic wafer and it dissolves in our system, Jesus essentially becomes de-Incarnated by our own digestive system.
- Do we have the power to change His Form?
I believe it's the Catechism which says that each time the bread is broken, Jesus is fully present in Each Section.
- If the bread were to be broken into 100 pieces, does that mean there are 100 separate Incarnations of Jesus?
Of course we cannot change his form but he can change us, metaphysically, in our body spirit. The point is to become one with Him, covenantally.
"Whoever eats my flesh and drinks my blood has eternal life and I will raise him up on the last day. For my flesh is true food and my blood is true drink. Whoever eats my flesh and drinks my blood remains in me and I in him. Just as the living father sent me and I have life because of the father, so the one who feeds on me will have life because of me." (John 6:54-57).
He is emphatically not being symbolic, with people who are accustomed to his allegorical and parabolic speech, so many could not brook it, and left him — disciples! (John 6:66).
- Would you still follow somebody who literally says you have to eat him?
What they couldn't see was beyond the Resurrection and that His Body would transcend reality as we understand and know it: He is God, and His Body is not limited to time and space — nor did He relinquish it to simply become spirit. He turned to the twelve to ask if they too wanted to leave and Peter spoke up and was willing to hang in there, trusting that He simply wasn't a crazy but would some how help them to make sense of it some day. He had faith in Jesus.
Many Catholics point to Aquinas for help on this issue, who used Aristotelian physics to explain this phenomenon, however, if you ask any physicist nowadays, they'll tell you that Aristotle is completely outdated in the field of physics and we simply don't understand matter and substance that way anymore.
No disrespect meant in these observations, I really am just trying to understand.
We look to Aquinas and the ancients, not for their scientific understand, but their philosophy and reasoning skills. Aquinas is a genius and still holds up; he cited ancients whom his contemporaries understood and followed to make points that they would grasp. Our understanding of the Eucharist does not derive from any of these individuals but from Holy Mother Church handed on from Christ himself, through His Apostles in conjunction with Peter, whose office is filled by the Pope.
Lastly, there is so much to share on the Eucharist, you should get some book like The Lamb's Supper by Scott Hahn if you want to more fully understand Catholic thinking.
I have only scratched the surface here and have gotten pretty lengthy already. Let's continue to dialogue, if your open, and we will help in any way we can.