You're it.
2 seconds sound clip from the Madagascar movie soundboard.
You can hear this line at 00:58:34 in the Blu-ray version of the movie.
Quote context
[...]
- Naw. I don't think I could...
- Hey, stop that! Hey, you're crazy!
- Okay, Marty, I'm it. I'm it. I'm it. You win.
- Come on, Alex, get in the groove.
- I haven't eaten in two days. My blood sugar's real low. I just don't have the energy.
- I don't think that's your problem.
[...]