Trevor: Brandon! Riley snuck over to my house and has a gun! I THINK HE IS GOING TO KILL ME!
Brandon: Are you serious?
Trevor: O SHI
It doesn't necessarily have to be fatal, because sometimes it is used in day-to-day instances
Student1: *catches breathe* I can't believe I made it to the bus on time!
Student2: Where's your backpack?
Student1: O SHI-
You search "Where is Chuck Norris" on Google: