Oh. My. Fucking. God.
It started out
as a fart.
and then it was
MORE THAN A FART.
I can't believe it ---
--- I actually just crapped my pants!
--- at work
on the bright side, looks like I'm going home early today!
Ride it out. Perform a half ass cleaning job in the bathroom, and then spend the rest of the day stinking up the joint. People WILL walk on eggshells to avoid implying that you crapped yourself. In fact, your feces are completely non-culpable once washed away, and you can call the wrath of HR down on anyone who tries to complain.
The burden of proof in on them in regards to the shit being in your pants at the time.
(Bonus points if you can incorporate Vasquez's "Somebody put shit in my pants.")