Percy (a.k.a. Percy the Small Engine) was a failed Bio-Fusion experiment.
"Thomas the Tank Engine: Shed 17"
Nothing is known about Percy's past before he was Bio-Fused into an Avonside saddle tank engine.
He did not survive his Bio-Fusion process and he was put on display during the off-season with other failed Bio-Fused experiments that were too unwell to work or already dead like him.
While Percy was on display, his eyes rolled into the back of his head, and his skeleton tilted out of his artificial frame, making his face turn to the side causing blood to spill from his smoke box. The crowd that were looking at him started screaming and running away from his corpse.
"Thomas the Tank Engine: Project G-1"
Some wher before his death, Percy warned Thomas about the Welsh Coal, when he was covered in it.
Percy's remains were later used as a weapon by G-1 when it was under attack by the British military. The carcass crashes into the military line, causing at least one tank to explode and several casualties.
Shed 17 Universe
- Thomas The Tank Engine: Shed 17 (stock footage appearance; does not speak)
- Thomas The Tank Engine: Project G-1 (does not speak)
- Percy's appearance in Shed 17 was actually footage taken from the nameboard segments of the TV Series, and because of that, he didn't have his own 3D model until Project G-1.
- On a live stream, Paul said that Percy's last name could be Parker, making Percy one of the few Engines to have a last name.
- Percy didn't speak at all in Shed 17 or Project G-1.