Sky began as a fan character created for a Friday Night Funkin mod, where she appears as an obsessive fangirl chasing Boyfriend through shifting forms during her songs. Phase 4 refers to her later, more extreme stage in that mod's escalation, which fans clipped and reused outside gameplay. The audio spread through soundboards and short video edits because the phase change was already a recognisable moment for players. It remains popular with FNF fans who use it to mark a final form, a meltdown or an over-the-top turning point.