Unsuspecting brown force

When you’re going to use the bathroom (#1) and you let out a fart and shit unexpectedly comes out. Similar to a shart, but you’re not wearing pants and you’re sitting on the toilet.

Can also be referred to as “brown thunder”.

Person 1 “BRB bro - I gotta go take a leak!”

Person 2 “ Okay I’ll wait here for you.”
15 min later..*person 1 returns*
Person 1 “ Sorry I took so long - I thought I just had to pee but I got hit with the unsuspecting brown force!!!”