The event is called "Poetry Parnassus" -- named after Mount Parnassus, known in Greek mythology as the spiritual home of poetry, the stampingground of the lyricist Orpheus and the hang-out for the Muses.
With their whips in their teeth, the riders try to manoeuvre their mounts through the scrum of horses, leaning down among the stamping hooves to pluck the carcass from the ground.