Some outcomes are so obviously predictable that reacting with genuine shock becomes its own kind of joke. The surprised pikachu sound cue captures exactly that irony — an exaggerated shocked reaction applied to a consequence absolutely everyone saw coming.
What this sound cue actually is
This sound is paired with a widely recognized, exaggeratedly shocked facial expression from a popular game character, used together as a reaction to an outcome that was entirely predictable. The pairing works specifically because the "surprise" is obviously performative rather than genuine.
Why the irony is the entire joke
Unlike a sound built for real shock, this cue's comedic value comes from the gap between the exaggerated reaction and how utterly obvious the actual outcome was. 
A man in a car with a surprised look on his face says " my reaction to that information... — view on SoundGIFs The bigger and more predictable the consequence, the funnier the mock-shocked response lands.
Where this sound fits best
This cue works perfectly for a predictable consequence following an obviously risky or ill-advised decision — someone doing something clearly unwise and then reacting with exaggerated shock when the predictable bad outcome actually happens. The humor depends entirely on the audience recognizing the outcome was never actually in doubt.
Self-inflicted outcomes work best
This sound lands hardest when the person reacting is also the one responsible for the outcome — mock surprise at a self-inflicted, entirely foreseeable consequence is funnier than reacting to something outside anyone's control.
Why this differs from genuine shock reactions
A genuinely shocking, unpredictable moment calls for a sincere surprise sound rather than this ironic one — using this cue for real shock undercuts the joke, since its entire comedic value depends on the audience recognizing the outcome as obvious rather than genuinely unexpected.
Comparing it to other reaction sounds
This cue's ironic, obviously-performative quality sets it apart from a genuinely restrained reaction like a sharp inhale sound effect for shock reaction edits, which is built for real, quiet surprise rather than exaggerated mock-shock.
Using it in your own content
Pairing this sound with a clip where the predictable outcome is genuinely obvious to any viewer tends to land better than trying to force it onto a moment that isn't actually that predictable — the joke only works when the audience is already a step ahead.
Conclusion
The surprised pikachu sound cue turns an obviously predictable outcome into its own kind of joke, relying entirely on the audience recognizing the irony. Browse SoundGIFs' meme sound effects collection for more reaction sounds built around comedic irony.