* In a general live performance sense, this is fairly common, for obvious reasons. Just a few of the things that can invoke it:
** You're the singer, and you've just forgot your lines or you've came in at the wrong place or you've fallen to VocalRangeExceeded. Or, alternately, you're one of the other members of the band and you ''notice'' the singer is in trouble. Similar for guitarists making major errors (or having lied about their skill level beforehand), and ''really'' a problem if the drummer or rhythm guitarist is the person having issues keeping the beat - that often induces a small version of MassOhCrap with all the other band members realizing just how bad the song's going to sound and how bad the gig is likely going to be.
** Someone has gotten sick or injured onstage or in the audience. This one easily turns into MassOhCrap as well, for obvious reasons.
** One of the band members' sound output is failing somehow. Worst is if it's one of the guitars (including the bassist), or the keyboardist, because that carries the possibility that the instrument itself failed (though it's usually only a loose connection) - and while most venues do carry extra mics for a singer to use in a pinch (or can patch him/her directly into the PA system with a lapel mic or a smartphone if set up for it and all else fails, though this is often avoided because it will make the singer ''much'' louder than the band), most don't have a stray electric guitar or bass or keys lying around, and even if the person has a backup, the show has to stop to set up his/her gear again for the new instrument.
** For a VisualKei band or other act that uses a lot of stage makeup, special effects, and the like, a SpecialEffectsFailure. If said SpecialEffectsFailure involves pyro, OhCrap and MassOhCrap are the ''best'' outcomes.
* [[{{vocaloid}} Gakupo]] reaction in [[http://www.youtube.com/watch?v=rV99NZmurVA Madness of Duke Venomania]] when he realize just who the girl in his arms really is.
* [[http://www.youtube.com/watch?v=udS5qBrBFqE GIRL YOU KNOW IT'S GIRL YOU KNOW IT'S GIRL YOU KNOW IT'S...]] (Unfortunately, there don't seem to be any videos on Website/YouTube that aren't either dubbed over or butchered.) For those unaware, this was the beginning of the end for Milli Vanilli.
* "[[http://www.youtube.com/watch?v=9Qi2m6NyUP0 But you could have heard a pin drop - when Johnny stopped and locked the door...]]"
* In "Dinosaurchestra Part 3" by LemonDemon, the time machine which the narrator used to go back to the late Cretaceous period and start a [[ALittleSomethingWeCallRockAndRoll rock band]] with [[EverythingsBetterWithDinosaurs dinosaurs]] can't make the return trip, and then..."What's that rock way up in the sky?"
* In the {{Gorillaz}} video for "Stylo", when 2-D and Murdoc realize that they are being chased and shot at by none other than [[spoiler: BruceWillis]].
* In the beginning of "Welcome to the Jungle," a singer briefly and subtly says "Oh my...god" before any of the intro gets through.
* In the song "Get My Gun" by D12, {{Eminem}} angrily threatens a fan with a gun:
--> Wassup, bitch?! (cocks gun) Autograph this! (click) ...Oh, shit.
* Speaking of Eminem, the title character of "Stan" is narrating the latest letter he's sending to his hero while his pregnant girlfriend is locked in the boot of his car and he's about to drive them all off a bridge to their deaths. He has a massive OhCrap when he realises ''just before the car goes over the edge'' that he's overlooked one fairly important point...
-->Well gotta go, I'm almost at the bridge now/Oh shit! I forgot! How am I supposed to send this shit out-
* In "[[FranzSchubert Der Erlkönig]]", the boy is increasingly terrified (and justly so) each time he tries to get it through to [[AgentScully his father]] that the Erlking is after him [the boy].
* [[Music/BlackSabbath OH NO! NOOO!]] [[http://www.youtube.com/watch?v=f4dpFjSFYX4&feature=related PLEASE GOD HELP ME!]]
** More or less mankind's reaction in the final verse of "Iron Man" when the titular time traveler, after being sealed away for centuries, is reawakened and proceeds to kill everyone.
* If you are or were a teenaged boy, you probably cringe when you hear the lyrics to the Everly Brothers [[https://www.youtube.com/watch?v=dDv4fnwCSg4 Wake Up Little Suzie.]]
* The final verse of Music/{{Nickelback}}'s "Animals" has the main characters [[AutoErotica getting busy]] in the protagonist's car by the tracks. Everything's going well until the girl notices that [[spoiler:[[ParentsWalkInAtTheWorstTime her dad is right outside the car and has caught them in the act]]. And worse, the keys aren't in the ignition because they fell on the floor in the middle of it]]. Oh crap indeed.
* The narrator in "One" by Music/Metalica has this when he realizes that he lost his sight, speech, hearing, and limbs due to a landmine, but his mind functions perfectly so he [[AFateWorseThanDeath is a prisoner inside his own body.]]
* In the Music/IceT song "Midnight" Ice-T, Evil-E, D, and Hen had just stopped two people from carjacking them. Ice then turns to see that the jackers had brought along a bunch of their friends.
--> Looked to my left, There were two more carloads, Niggas in hats and hoods, In an attack mode, And they hadn't yet begun to fight