The "Smiling Acid" design typically features a yellow circle with two oval eyes and a curved mouth, though rave variations often include "melting" or "trippy" effects to reflect psychedelic experiences.

The (often simply called the "Acid Smiley") is the definitive icon of the Acid House music movement and 1980s rave culture. While originally a corporate logo, its adoption by London club scenes in 1987 transformed it into a global symbol for hedonism, unity, and psychedelic dance music. The Evolution of an Icon

DJ Danny Rampling is credited with bringing the smiley to the rave scene. After visiting Ibiza, he opened the club Shoom in London and used the symbol on flyers to represent the "love, unity, and happiness" of the new sound.

The strange, tangled history of the acid house smiley - Red Bull