Sulfur comes from Sprunki Pyramixed, a fan-made Sprunki mod inspired by Incredibox where each character adds a loop to the mix. In the horror version the bright designs switch to darker forms and the music turns minimal and tense. Clips of Pyramixed characters spread through YouTube and TikTok playthroughs, fan mixes and edit communities, where short isolated loops are often shared on their own. Sulfur stayed popular with editors because its loop works outside gameplay too, as a standalone cue for dread, corrupted characters and dark transformations.