Flipyap

"You killed Flipyap! Or Yapflip, was he... It was Yapflip... No, Flipyap is his brother. Don't tell me I don't know Flipyap! Flipyap and I went to Nipple Academy together! And.... and he's dead..."

- A Grunt

Flipyap is a Grunt mentioned by another Grunt in a long comment that can only be heard with the IWHBYD skull. According to another Unggoy, he and Flipyap went to "Nipple Academy" together and that Flipyap was the brother of Yapflip.

Flipyap is only mentioned in an Easter Egg in Halo 3 for humorous purposes, as is "Nipple Academy", which refers to the Food Nipple feeding tubes used by the Unggoy.

Trivia

 * The quote can be heard here.
 * There is also a chance with the IWHBYD skull on that you can, overhear grunts talking, saying, "Cover me, I'm going in." "I'm not going to cover you, it's your fault Flipyap got killed."
 * There is another chance that on Legendary on the Level Sierra 117 that if you kill all the Grunts, Brutes and Jackals, a Grunt will say this line.