Yapflip

"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, when another has been killed

Yapflip is a Grunt mentioned by another Grunt in a long comment that can only be heard with the IWHBYD Skull turned on. Yapflip is, apparently, Flipyap's brother. Flipyap is mentioned by Bungie for humorous purposes only (as is Nipple Academy, which refers to the food sacs Grunts use: food nipples).