Bowser is the main antagonist of New Super Mario Bros. He is also a reoccuring and final boss of the game.
Bowser is fought at the end of World 1-Castle of this game. Bowser simply attacks with fire breaths and stomps. Mario can either defeat him by hitting the switch or by throwing fireballs at him as Fire Mario. Either way, Bowser is plunged into the lava and his skin gets burned off turning him into Dry Bowser.
Bowser is fought as the final boss of the last level in the game. Bowser Jr. revives his dad back to his old self and aids him in the battle with Mario. In this battle, Bowser can launch an assortment of fire breathes while Bowser Jr. attacks by throwing shells or hiding in his shell and attempting to slam into Mario. This battle can be made easier by coming has Fire Mario. Bowser Jr. must first be taken out and after he is, Bowser grows furious and his attacks become more frantic. Bowser can then be taken out with the switch once an opening occurs or with fireballs until he is defeated and Peach is saved.