Angels reproducing with humans possible?

[Lafon]

Noting that some have conjectured Satan manifested himself as a serpent, or that other angels manifested themselves as human being, that is to say that invisible, incorporeal angelic beings to whom God endowed with NO creative abilities, transformed themselves into that which is substantive or any other corporeal type of being, seems, to me at least, to be rather far flung. There's just nothing in the Scriptural record to justify such a speculative conclusion!