Mario (Donkey Kong Jr.)

While Mario is depicted as a hero for the most part, he is enemies with Donkey Kong and Donkey Kong Jr.. These are his villainous actions.

Donkey Kong Circus prequel
Note: This is the 2nd game released in the Donkey Kong series but takes place before the first game. Mario was a carpenter who had come in possession of a Kong and his son, Donkey Kong and Donkey Kong Jr.. Mario, unwittingly, mistreated the ape by putting him in a circus. In the circus, Donkey Kong had to use his legs to balance the barrel he was on, juggle pineapples and avoid deadly flames.

Donkey Kong (game)
Mario was a carpenter who had come in possession of a Kong and his son, Donkey Kong and Donkey Kong Junior. One day the ape captured his girlfriend Pauline and took onto a construction site. Mario went on to rescue his girlfriend avoiding Barrels thrown at him by Donkey Kong and a fire started by the ape. After going through four different areas on the construction site Mario rescued Pauline and Donkey Kong was recaptured.

Donkey Kong Jr. (game)
Mario went on to imprison Donkey Kong in a cage. DK Junior went on to try and rescue his father. Mario attempted to stop the young ape and released various types of traps mainly consisting of animals. Junior eventually did make it to his father and the two returned to Donkey Kong Island just after Donkey Kong made a shot at Stanley the Bugman's greenhouse.