You have a million options at your disposal and you think it's witty enough put pen to paper(fingers to keys) for the one response that 99.9% of the population could retort with. You guys really strained your brain muscles on that one.
Stupid or not, that's for you to decide but at least the OP had an original thought. As long as you're putting someone down, you could at least come up with something better than "I know you are what but what am I".
+1 to the OP for creativity.
-1,000 for the people who weren't even smart enough to come up with their own idea for an insult.