I know you are but what am I

• I know you are, but what am I

Uncertain, but dates back at least to the 1970s, as reported in Lee Thayer, Communication (1974), page 21. Often attributed to Pee-Wee Herman.

I know you are but what am I?

1. (rhetorical question, colloquial, childish) Assertion that an insult made by the party to whom the phrase is directed is actually true of that party, and not of the person using the phrase. Usually considered to be a playground taunt.
   • 2005, American Numismatic Association, The Numismatist, page 14:

     So when Mr. Macchia states that people who collect state quarters are fools, my son says I should reply, "I know you are, but what am I?"

   • 2003, Mark E. Jones, Echoes of Heaven, page 7:

     At this point Johnny changes tactics and hollers, "I know you are, but what am I?" and the voice echoes, "I know you are, but what am I?"

   • 1984, McCall's, v. 111, page 62:

     I know you are but what am I? Jeannie would say out loud, whenever I mouthed a name at her.

• it takes one to know one
• I'm rubber, you're glue