A second-slot alternate weapon that can be unlocked for the Sniper class in Team Fortress 2. It is a jar nearly full of human urine that can be thrown at enemies to cover them in the contents or thrown at allies to douse them if they're on fire. Enemies covered in urine will always take mini-critical hits from any damage dealt. It is also the most commonly used replacement for the Sniper's default sub-machine gun. The name given is a portmanteau, or combination of the words 'karate', and 'jar'. It is even sometimes referred to as karate in a jar.
It is the hardest weapon to mod in Team Fortress 2, and almost all skins of Jarate are recolors of the liquid.