Horsemanship is a keyword ability that functions similarly to flying. It appears in the Portal: Three Kingdoms set and does not appear in the Double Masters set. This means that in most cases Rolling Earthquake will simply deal X damage to each creature and each player, even creatures depicted on horseback in their illustration.
Random a card of Magic: The Gathering (MTG), but you can also roll the D20 dice, random a Planeswalker, have fun with the random rules and more.
