It was a typo or pingyin input mistake. Hunhun
meant to say "finish running Marrathon"
(Pao3, Wan2, Ma3, La1, Song1), but his
post goes "抛丸"Ma3 La1 Song1, which,
actually, turned out to be very much to the
point.
Hunhun's sentence became "抛丸 Marrathon, I was
full of joy..." or something to that effect.