Perseus Academic: Nature of the Beast by Adam Mansbach

An alien race of religious extremists plan to honor their deity

through the ritualistic annihilation of our planet. The only man who

knows this is Milan Marlowe, an unstoppable media baron who sees

opportunity everywhere.

Earth's only move is to engage the invaders according to their

holy law and issue The Challenge of the Heretic — a winner-take-all

gladiator battle for our right to exist. Marlowe launches Beast Wars,

a televised interspecies tournament designed to select Earth's

mightiest champion. On a decadent private island, sharks, lions,

gorillas, and polar bears square off to the delight of screaming

fans oblivious to the sky-high stakes.

Enter Bruno Bolo — single father, blues belter, and alligator wrestler

from the swamps of Florida. Beset by personal demons, corporatized

killer sharks, Yeats-quoting pit fighters, and looming alien eradicators,

Bruno will emerge as our desperate planet's final hope.