The prototype version of "Hippocampus" differs quite a bit from the final production version.  In the prototype, the seahorses are all wearing Christmas hats; there is a lot more ocean "vegetation" floating around; and the treasure chest is featured on the reverse with larger "gems".  Only one of these prototypes remains available.  
The Hippocampus Ball Ornament - Prototype
Part of the  Christmas Past collection
Handcrafted in Poland
Made from glass
Approximately 4 inches tall (10cm)
Made by Thomas Glenn Holidays