Lol, well, I'm sure he thinks your enclosure is his private property!! And of course he wants to enjoy it. Keep an eye open, he will surely return one day :))
It's a toad, they live on land. I accidentally dug him up a few week's prior to this while building the fence. He hopped away into the woods indignantly, and re-appeared on my deck a few days ago.. He had to climb up the steps somehow, and climb the cat fence high enough to squeeze through the 1" square fence to get there. I had trouble squeezing him back through the fence, so it's REALLY a mystery why he went through all the trouble in the first place! I think he thinks he's a cat....