Joule,
I have never meet Xanthos in the flesh. I do not know exactly how he looks. Yes, it is highly probable that he is human. However, I don't know this for a fact, and can only go by what he has said here, as I have no reason to doubt his veracity. Therefore, as far as I'm concerned, Xanthos has told us that he is a horse, and so he is a horse. I have not lied to Gail. My intent in even mentioning it would be to see P & H's explanation of a "hit man".
Whether or not he is playing a game that has gone too far is another matter entirely, and up to him whether or not he wishes to continue it. It is not my decision to uncover something that I do not have proof is a charade.
Parker & Hardon ALREADY seem "utterly convinced the Gamma Unit is whacko", to use your phrase. I sincerely doubt anything else she says at this point will make a difference. Besides, Gail will decide what she does or doesn't want to say. She's completely ignored things we have sent to her in the past, and she may very well ignore this as well.
-Psiclops