Ninjarrhea
An unmercifully stealthy strain of diarrhea which springs upon unsuspecting persons at inopportune times. Almost always without prior warning and leaving just as quick as it came. Often the end result of reckless flatulence.
I was visited by some Ninjarrhea today at my job interview. Remind me never to eat at Taco Bell before important events. I don't think I got the job.