Filandrius wrote:
Please, PLEASE let us know what it is. My curiosity is stronger than my appetite.

At first glance it really looks like a dead chestburster. For that it looks great.

It is indeed a part of a chestbuster.
I bought it on an belgian eBay-like website...
It is molded on a vinyl chestburster and the plate is acid-burnt.
It could have been better regarding the "content" of the Chestburtster tough but anyway it stays a great item in my always-growing collection.
If you are interested I can contact the seller to ask if he could make (an)other one(s).
Regards,
Sven