Fortunately it wasn't plugged in at the time.
Why did he do it? To annoy his sister, of course.
And also because the desire to pee on things seems to be genetically inborn in males.
Hence this annoyingly ubiquitous bumper sticker:
And you can even go to the website above and have this little guy pee on anything you want!
I don't need to. I have my own little guy.