Five twice over -once for coming so close to a ludicrous 90s-rock version of the Itchy and Scratchy theme, and twice for the Jabberjaw reference in the very last segment.
This was actually based on an obscure mature-readers-only comic. Think of Swamp Thing while Alan Moore was at the helm and you've got a good idea of what the comic was like. I'd normally say they Did Not Do The Research, but in this case it's more like They Just Didn't Care.