Not a sheep. Christ is THE sacrificial lamb. The one and only sacrifice to God, both priest and victim.
Behold, the Lamb of God, who takes away the sin of the world!
and also:
And between the throne and the four living creatures and among the elders I saw a Lamb standing, as though it had been slain, with seven horns and with seven eyes, which are the seven spirits of God sent out into all the earth.
and of course:
Christ, our Passover Lamb, has been sacrificed for us.
Christs is NOT a victim and never has been.
He offered Himself. Nobody took His life from Him. He gave it.