The harlequin doll was a gift from Dad to John for his birthday. When John first entered the living room, he found a big box from his Dad to him. Upon opening the box, John found the doll, much to his disdain. He sat it on the sofa and attached the Fake Arms to the doll, making it AT LEAST a million percent funnier. Later on, the doll suffered damage when some broken glass was pushed out of John's Sylladex. Rose then prototyped the Kernelsprite with it, causing the Kernelsprite to change to look like the doll's face and remaining arm.

The harlequin doll is not to be confused with the "Accursed Mascot" resembling Jack Noir. Since the "Mascot" appears in Dream John's bedroom, it may be responsible for John's unconscious drawings in both those rooms, which in turn leads to his father's belief that he likes clowns and, later, to the unfortunate prototyping of the harlequin doll. The "Mascot" was in fact implanted into John's dreams by Gamzee as a form of revenge, since he knew it would ultimately result in the rise of Jack Noir.

The prototyping of the doll started a chain of events that lead to Noir's rise to power by pushing him over the edge and into rebellion;

1. The Black Queen ordered all Dersites to wear the comical hats after the prototyping of the doll
2. Jack Noir refused to wear his
3. The Queen came and argued with him
4. He attacked her with the bunny
5. He claimed the ring for himself
6. He eventually became Bec Noir and majorly ruined everything

Missing eyes and arms are a recurring motif in Homestuck. Although most are a result of prototyping the doll, Vriska Serket and Spades Slick's missing eyes and arms are unrelated.