As in "Little Nicodemus."
That's what Nicodemus thought Jesus was trying to create; a little physically reborn Nicky!
That of course comes from Nicodemus' interview with Jesus in John 3, which I have recently been studying.
There are many possible ideas as to why Nic would say "How can this be?" when Jesus told him that he needed to be born again, but I frankly find that Nic just didn't get it. He just could not grasp or believe that new birth was a requirement for entrance into the Kingdom of God. He figured, as he had been taught, that he had only to be obedient to the law already being a Jew, and hence, favored.
But Jesus was clear; the problem is not one that can be touched by rituals and such. Only a radical transformation of the entire person can make a person fit for the Kingdom.
Nicodemus' inability to understand says a lot about Jesus' words to him. Nicodemus had said "we see that you are from God". Jesus' response "that unless you are born again you won't see the Kingdom of God" implied that they didn't really see as much as they thought. In fact they could not, having not been born again. Nicodemus' lack of understanding simply confirmed Jesus words.
Its a nice bit of irony really, and highly applicable to us today:
We tend to think that we need to conform rather than be transformed. The fact is we can't conform to God's pattern apart from being transformed (Ro. 12:1-3). We can try to conform otherwise, but then we'll be like Nicodemus.
The problem of course is that, unless we have someone to tell us we don't see like we think we do because we are in need of transformation, we probably won't get it when we go to the Judgment and are found wanting.
That's not ironic though. Its tragic.