If you run a play near your own goal line, and get a penalty, if that penalty yardage takes you beyond the goal line, it counts it as a safety, instead of half the distance to the goal! See example from game log below:
Rush by Marin, C. for 8 yds. Tackle by Hawkins, C..
Michigan Penalty on Lange, J.: Unnecessary Roughness.
The play results in a SAFETY!