John 6:53AWTTW.Jesus said to them, "I tell you the truth, unless you eat the flesh of the Son of Man and drink his blood, you have no life in you."
Speaking of miraculous signs :-)
John 6
v. 30 "So they asked him, "What miraculous sign then will you give that we may see it and believe in you?" And they picked the example of manna in the desert. And Jesus came up with an analogy for them. The 'miraculous sign' is ME! I'm the living bread of life that came down from heaven! "For my Father's will is that everyone who looks to the Son and believes in him shall have eternal life and I will raise him up at the last day".
I don't think he's saying, since you asked, here's the miraculous sign I'm going to give you: when you take communion, I'm going to turn the bread and wine into my flesh and blood, and when you eat and drink that, it will turn into my real flesh and blood, and that help give you eternal life.
John 6 is pointing to Jesus. He's talking about the importance of faith in Him in order to live forever.
It reads like a metaphorical lesson.
And then some disciples turned away. But not because they were grossed out by eating flesh and blood, but because they didn't believe in Him, because the Father had not enabled them. And He pointed it out and they left.