Place it at the first sighting in a clip, then follow it with the Enemy Spotted cue as the threat closes in and finish with the FNAF Jumpscare Scream when the attack lands. Keep it at the front of the sequence so the warning sets up the attack that follows.
About this sound
This is a sharp, very short alert cue lasting just over half a second, built around the moment a poison headcrab spots its target and raises the alarm. It hits fast and leaves no room to relax, giving a tense, jumpy feeling that something dangerous is suddenly close and ready to strike.