Mario and princess Peach are having a walk when suddenly Bowser Jr. kidnaps the princess while Mario is distracted.
As Mario gets to Toad town, a giant Bowser is bombarding the castle with disastrous attacks.
Bowser is sometimes also called King Koopa and Lord Bowser.
Bowser is the leader of the Koopa race (named Koopa Troopas), a turtle-like people charged with kidnapping Princess Peach so Bowser can take over the Mushroom Kingdom.
Luigi, Bowser and Princess Peach should come to your mind.