King Bowser is the main antagonist of Illumination's 13th feature film The Super Mario Bros. Movie, an adaptation of Nintendo's Mario franchise.
He is the tyrannical king of the turtle-like Koopa Troop race and Mario's arch-nemesis, who is constantly plotting to expand his kingdom by conquering the Mushroom Kingdom. Bowser is in love with Princess Peach, and his attempts of conquest almost always include kidnapping her in one way or another.
He will be voiced by Jack Black, who also voiced Po from Kung Fu Panda franchise,Lenny from Shark Tale and Carl Denham from King Kong.