A-78's spawn is ULB-278/Billy's voice saying "run" but extremely slowed down. Its spawn is also around 160 decibels, with your volume at max. The sound is also a song called Nom Nom Slow down the sam (12) file in the sounds menu 9 times, and set the volume for the sound at max. A-78 is a really friendly entity, and will warn you whatever entity is coming. He will guide you through the room and NEVER despawns. His X-Variant, X-78 DOES despawn after a WHOPPING 1 hour. Unfortunately, A-78's X-Variant is sensitive to flashlights, and takes 99 damage per tick.
@HRLR2023 and me obviously
