It's quite simply the most retarded comeback someone makes when they've completely lost the argument. This statement signifies that the argument has gone to a completely immature level. Below is a hardcore argument starting with the immature statement :)
Person 1: I know you are, but what am I?

Person 2: Good question. What are you?

Person 1: Wow, you're so dumb, you don't even know what I am?

Person 2: You're so dumb, you can't even answer my question.

Person 1: I don't answer stupid questions. Sorry.

Person 2: Then you shouldn't have made your first one.
by Searingwolfe July 13, 2011
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An act of utter exuberance over the cuteness of another individual
A newly-in-love couple is joking around and having a good time with each other...

Boyfriend: I like you. A lot.

Girlfriend: *cuddles him and gives him one hell of a kiss*
Boyfriend: What am I gonna do with you!?

(Enter in to sexy time mood if desirable)
by SpudWillicker February 18, 2014
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The best come back to any insult in the history of the planet. Using this phrase will completely destroy and annihilate your component, so only use of absolutely necessary. (Say they think Sam and cat is a good TV show)
Fred:Our mom just died

Joe:I know you are but what am I
by •*MentallyMaggie*• March 9, 2020
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the most offensive comeback to ever be said. this comeback makes "your mom" seem like a nice thing to say. this comeback can out roast any insult thrown your way.
person one:You gay

person two: i know you are, but what am i

whole everyone else: OOOOHHHHHHH
by BlueStripes March 19, 2019
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