[[WMG: D―Day is a Time Lord]]
He decided to spend some time observing 1960s college life in the most badass way possible, so he created a whole BadassBiker persona to fit the time period and spent four years getting into as much WackyFratboyHijinx as humanly possible. He didn't need to get a degree because he already had centuries of education under his belt, so he barely showed up for any of his classes (hence, he has no GPA). By the time the parade riot came around, he decided he'd seen enough of 1960s America, so he went off to explore another corner of the universe (hence, his whereabouts are unknown at the end of the movie).
* Adding further fuel to this particular fire… When the members of ΔΤΧ are checking the time for the Homecoming Parade – what is D—Day looking at? [[spoiler:An open pocket watch!]] In the words of Bluto: '''“HOLY SHIT‼”'''
[[WMG: D―Day went from biker to law enforcement after the movie]]
He resurfaced ''as'' the county sheriff in a certain [[MyCousinVinny small town in Alabama]].
[[WMG: Bluto comes from a rich and powerful family.]]
Come on, how the hell else could he have become [[spoiler: a U.S. senator]]?