A large herd of roaming freshman typically found on a college campus. There is usually an alpha-male present, i.e. one member of the pack who has connections to elder members of the campus, thus allowing the frosh pack to drink at the elder's watering hole.
A frosh pack, although usually docile, may become more aggressive as the night goes on and the drinks go down. As a result, approach with great caution and never look the alpha-male straight in the eye.
An unusual amount of books/notebooks/binders in one's schoolbag, resulting in an overstuffed backback that a freshman would carry around the first months of school.
Woah, what do you have in your bag? It's looks like a froshpack.