Never seen it before (not that I am a zoanthid aficionado) and that is one wicked looking polyp. If it truly is the first one to hit the trade then thats a steal of a price at its current bid. I would venture to guess whichever vendor picks it up they will end up selling it $150+ per polyp for a good year at least. It is actually a pretty sound investment, if it is the first to the trade. Besides of course the person selling it.
I've never purchased coral off of ebay, but whenever I have purchased other stuff the price usually almost doubles in the last 15 minutes, thats why i guessed so high.
IDK. If they grow this puppy out they will have a couple grand worth of polyps in a couple months... or a $500 frag plug where this polyp was before it melted.