Pegacow showed up on classroom whiteboards when teachers weren't looking — a cow with wings and a spiraled horn, in the corner of the board, before the bell. Some teachers erased it. A few let it ride out the period.
Years later it turned up on a college physics exam, in the space where a magnetic field question was supposed to be answered. The grader gave it half a point.
No formula, no answer, no shame — just a winged cow talking a stranger into being generous. Pegacow has been doing that ever since.