According to Gwen Stefani, bananas is what "this shit" is. Soon thereafter she informs us how to spell bananas.
Orange County Spelling Bee:
Bee Man: Ms. Stefani, please give a definition and then spell "Bananas."
GS: This shit is bananas, B-A-N-A-N-A-S.
Bee Man: Genius. Pure Genius. Give her the 1st place trophy right away. Ms. Stefani, you are the bananas.