Honestly not the weirdest behavior you’d see in campus, and could almost be wholesome. Guy’s down on the ground interacting with his dog; what’s wrong with that? Also: it’s at night - could they see he was actually eating grass, or did it look like he was just playing with his dog?

Also also: college campus… night… couple sitting on a bench… “sitting.” College couples never only sit on secluded benches in the dark. OP probably interrupted a handy.