Mystery of the shiny purple lobster in Key West

I don't know what this is because there is no sign but it looks like a stack of lobster traps forming an arty sculpture.  It's in Key West Bight / harbor.

That is mystery number 1: what is it, and who did it?

When I passed and took this photo it was about 9.30 this morning.

And, looking carefully, I saw a shiny purple lobster at the top.

But when I walked back, 20 minutes later, it has GONE!!!

That's mystery number 2: where has the shiny purple lobster gone?

If you can answer either, or both, these mysteries, please leave comment below.  I'd love to know.

Updated January 2013: Mystery solved.  It was the early stages of construction of a Christmas Tree, slightly eccentric and Key West Bight style.

Here's a pic from January of it all finished and lit up.