Of course you're not compelled to share my views. Im not sure myself. Just observed a weird shape on its back and that staying thus is quite abnormal. And it's a well known fact that some people would do anything to shoot a funny video. Some even let own children get knocked for that. You can hammer a nail into the bench, pierce superficially the frog's skin and slide the nail under the skin; then some glue to fix the butt (notice the wet area next to the butt) and the frog wont die or move. Can't say it was done so, just considere it could have been done so. Or maybe now frogs can be taught to sit properly like humans. I rather believe the former than the latter, but again, you're free to believe the oposite.