Put this laugh at the reveal beat, not during dialogue, then follow it immediately with a FNAF jumpscare scream if the moment escalates, or precede it with a danger alarm to build the fake-out before the character turns.
About this sound
A short, distorted laugh performed in the voice of Chara, pitched and glitched to sound corrupted rather than playful. It feels unsettling and manic, turning a childlike giggle into a threat that makes a scene feel wrong on purpose instantly.