It is the injective drug similar to morphine. It's other name is "noofin" which is the same sort of drug but little stronger. Drug users mostly from Nepal use this drug mixing with Avil and Diazepam. The trip is similar to the Heroin.
The religion of centered around the well respected "Notch" or Markus Persson, Dedicating him as the savior and murderer of bordem.
Steve: "PRAISE THE MIGHTY NOTCH!"
Other example:
Steve: "Notch dammit!". Commonly used after an explosion of a creeper, Usually only practiced in Notchism.