Jump scares

This is generally seen in western horror or horror aimed for younger or action-oriented audiences.

Commonly this occurs in a somewhat quiet scene with dim lights where something highly visible, possibly with added ligths, glint or glow suddenly jumps right in front of the player likely accompanied by a loud and equally sudden noise or situational music.

Jump scares rely on provoking a reflex reaction (the "jump") from the player rather than actually scaring them (such as making them unwilling or cautious to continue or even stopping playing entirely). The suddenness startles the player, causing the previously quiet mild scene to turn hectic, which prompts various reactions from player which are similar to what actual panic attack might have.

Validity of these as actual horror is often debated and derided, and commonly contrast with things like psychological horror though neither does exclude the other. Though it's somewhat rare to see jump scares and psychological horror together as jump scares easily dissolve what psychological horror tries to maintain.

Contrast: psychological horror