OR, "Revenge Tastes Like Baked Potato."
SO, spoilers. I haven't actually played Portal 2. XD
What I did do was watch a full playthrough about a day after the game came out so I could be on top of all the memes and injokes about the games. And because my computer would explode if I tried to play games on it.
I would like to imagine that Chell would just like to mess with GLaDOS every once in a while. Oh, GLaDOS. You were so adorable as a potato.
Also, this is going to be available at A-Kon. Hurray for progress! 8'D
Done in Photoshop over a period of a few days and cgtextures were used as well.
Portal 2 is property of Valve