tsuwm, that's not a rat. That's Yakko from the Warner Brothers cartoon of about 5-6 years ago called Animaniacs. I think he's supposed to be a dog.
The premise of the story was that Yakko, along with his brother Wakko and their sister Dot (they called themselves "the Warner brothers . . . and the Warner sister) were cartoon a long time ago, but came out of the paper and wreaked havok around the studios. They were then locked up in the WB water tower and left there. The show began with them escaping from the tower. The show itself, though, was more of a variety show, with various short stories, songs and "the Wheel of Morality." All of it was, of course, totally in jest (as all good WB cartoons are.)
I can't believe I'm explaining a cartoon. Ah, but that show was a staple of my pre-teen years. 
