The Sia doppelganger was the disguise of Sia's trainer.
Physical appearance[]
The doppelganger is a monster of an unknown species; although she is sometimes referred to as a ghost, there is little evidence to judge the accuracy of this description. She was a slender woman with light blue skin and wears the signature wig of musician Sia, an oversized wig that is blue on the right half and black on the left. While the wig partially obscures the Doppelganger's face and completely covers the eyes, what is visible is a large mouth with red lipstick and yellowing, vampire-like fangs. The Doppelganger also wore a black jumpsuit with long tattered sleeves and which covered her entire body except for her head and hands.
Personality[]
The doppelganger could be best described as a "catburglar" in the literal sense. The doppelganger is a thief that prefers stealth over aggression, targetting locations when few witnesses are present and evading confrontation after acquiring the jewels she is targetting. However, while she attempts to prevent her crimes from being noticed, she exhibits very strange behaviour during her heists. To support her catburglar character, she is sometimes seen crawling on all fours, often on walls and ceilings, performing very intricate, acrobatic movements when on the ground, and hissing at witnesses in an attempt to scare them away.
History[]
Scooby-Doo and Guess Who?[]
Season one[]
Sia's personal trainer and chef wanted to start a Pilates studio, so to fund her ambitions she used the disguise to steal diamonds from the nearby jewelry stores and frame Sia, her boss, for the crime. She was first seen robbing a jewelry store, where security footage of the crime was recorded and examined by Mystery Inc. The group encountered the Sia doppelganger a total of four times: once in the pantry, once in the nearby Sparkle House, once in their bedroom and finally in the play room.

Sia's trainer unmasked.
During the final time, Mystery Inc. deliberately lured the doppelganger into appearing, then captured the monster with a very fast carousel that launched the monster into a cotton candy sign. Sia's trainer was exposed as the doppelganger and jewel thief and was subsequently arrested.
Appearances[]
- Scooby-Doo and Guess Who?
- 111. Now You Sia, Now You Don't! (no lines)