The Walther P99 is a semi-automatic hammerless pistol designed by Horst Wesp and developed by Walther Arms in Germany. It is also one of the firearms used by fictional agent James Bond alongside his handy Walther PPK.
In Mario Warfare, the Walther P99 was acquired by Mario who was on his way to save his brother Luigi from the Hammer Brothers. It was knocked out of his hands a Sledgehammer, however it was re-acquired by Luigi who shot at various Shy Guys while Mario carried him on his back. It was then taken by a member of Smash Club upon their arrival. The version carried by Mario is actually modified with the use of a rail attachment system with an all black finish.