By enchanting Boros Reckoner with Pariah, you cleverly redirect any incoming damage meant for you directly onto your own minotaur. When you cast Wheel of Misfortune, you simply choose an arbitrarily large number; if it happens to be the highest number revealed, the spell attempts to deal that massive amount of damage to you. Thanks to Pariah, that damage is soaked up by Boros Reckoner instead, instantly triggering its ability to fire that exact same astronomical amount of damage right at an opponent.