George Randal.
It's been the official drink of the ROC since 2013.
It's a lot of fun.
There are a lot of traditions surrounding it, but it started with a member of the athletic department giving it out to all his friends.
These friends started bringing it to the line outside the student section, and the rest is history.
Here's a Universe story on it:
http://universe.byu.edu/2014/03/11/1unique-drink-rocs-the-byu-student-section/
Bill Walton's had it before, and he remembered it last night.