My bearded dragon did the same thing. Once I realized it was doing me a favor, I was ok with itI prefer this behavior. It's a pain in the ________, until you realize you don't have to clean the rest of the cage. One of my monitor lizards is the same. I was annoyed until I compared the time it takes to clean the water dish poo'er, compared to the one that just goes anywhere. For the most part, change the water dish = cage is clean. Easy and simple.