The Knife is the standard close quarters combat melee weapon in Modern Combat 2: Black Pegasus.
The knife used in Modern Combat 2 is a KA-BAR knife. It is commonly used in missions that feature stealth and/or reconnaissance. It can also be used in the online multiplayer. The knife is triggered by tapping the melee button when near an enemy. The knife will always kill an enemy in one slash. Enemies are seen using them in interactive cutscenes but in normal combat will hit you with whatever weapon they happen to be holding. This is not a one-hit kill, but deals a lot of damage just the same.