What is this strange blue orb?

I took this picture on Ft. Lauderdale beach in Fl. I graduated with a BA in Studio Art with a concentration in Photo and i have never seen anything like this blue orb at the top of my photo. It wasnt in any other photo. i didnt see it when taking the picture and i have no idea what it was. water spot? my most logical guess. but it sure doesnt look like water. any have an idea what it could be? spirits maybe??? lol...

Looks to me like a drop of water

That's what it looks like to me too. Hanging from your lens hood?
What I can't figure out is why it appears to be more in focus than the rest of the picture or how it got there.

Considering the location, it could be water, but it's pretty much in focus for a drop of water hanging on the edge of the lens. And since you said this is the only image it appears on, I'm thinking a clear purple beach ball swung by the shot and you didn't notice it at the time. Either that or UFOs. :P

UFO no doubt!
The truth is out there! :D

I think james has it and I too now think it is a beach ball flying by.