I forgot to mention something very important about Ezekiel's 666 transformation...
Ezekiel 3:3
"And he said unto me, Son of man, cause thy belly to eat, and fill thy bowels with this roll that I give thee. Then did I eat it; and it was in my mouth as honey for sweetness"
In order for Ezekiel to receive 666 on his forehead, he had to eat a Scroll first. This is a very important clue as to how the Unsaved will receive the Mark of the Beast.
A Scroll in the Bible is a reference to DNA. It is the Word of God that becomes flesh. What God is teaching here is that it is possible for Humans to eat something to cause their DNA to be edited and altered.
Think Adam and Eve and the Forbidden DNA they ate.
More specifically, this DNA change creates a new identity. God gave Ezekiel a 'new identity' in order to 'blend in' with the Rebellious House.
The bottom line here is that the Mark of the Beast is a DNA alteration that will give the Unsaved a new identity, hence...
Matthew 7:23
"And then will I profess unto them, I never knew you: depart from me, ye that work iniquity"