Oh Crap/Web Animation

"Simmons: "What? They sent another team member? Why would they do that? That doesn’t make any sense- (sees that it's Meta) OH, FUCK! (starts to run away) Welcometotheneighborhood, seeyoulater!"
 * Tex in Red vs. Blue gets this moment when Donut lobs a plasma grenade over an incredible distance, square into the cockpit of the tank she was driving.
 * Everyone is one the receiving end of this at least once, although their reaction is less "oh crap" and more "son of a bitch!"
 * In Recreation Episode 12, Donut is cleaning up Blue Base when he's approached by what he thinks is a new Blue soldier (it's actually the previous season's Big Bad, Meta.) Donut, being Donut, tries to strike up a friendly conversation with it, evading its attempts to kill him by near misses. Simmons then arrives, Donut tells him about the new soldier, which leads to this:

"Washington: Do I hear a... (Grif drives a Warthog jeep through the wall)
 * Red vs. Blue: Revelation, Chapter 3:

Washington: CAR?!?"


 * When The Meta attaches the memory unit containing the recently captured Tex to his armor
 * The Meta is the living personification of this trope he even has his own Theme music which makes the Imperial March Jaws theme and Psycho Strings look tame in comparison
 * The Demented Cartoon Movie: An underwater diver recites the trope by name upon realizing that the "Bubble Fish" he has been tracking is actually Zeeky H. Bomb.
 * Happy Tree Friends is a total definition of this trope. Nearly every episode has it's Oh Crap moments (save for just a few). In the fanimation "All Work and No Belay", before Lumpy, he notices what will happen and holds up a sign saying "HELP?".