Transsubstantiation Is Foreshadowed

Transubstantiation just means that the substance has changed. Why while the appearance has remained? I mean, we read in genesis about angels who take the form of men. A christ is the passover lamb and as well as the new moses. And he wants us to eat him, the new passover lamb. So i would say there's multiple ways in the old testament that that that's foreshadowed. And i think thisis the earliest christians understood it.