Rat shaun was a former train conductor, subway guard, and bank robber. He perished in the sewers and was later hired by Lady E to capture "Cornelius" one of the friends of the ghost hunters "Jack" and "Parker" from season 2 from lego hidden side tv show.

Rat Shaun is a flying ghost wearing a tattered yellow sports jacket over a white button down shirt, a black bowtie, an vest blue, he is also wearing a black conductor's hat with a yellow tag connected to an orange stripe. He is holding a flashlight in his left hand and his rat's tail in his right. A mountain of smaller, brown rats is formed on his back, along with groups of two-three rats encircling his torso while all his full body is yellow color of skin to clothes.

Rat Shaun was a former subway train conductor in newbury city who had to turn to bank-robbing to pay for his sick daughter's medical bill. He was chased by the authorities and cops into an abandoned subway tunnel, where he got lost and never came out alive (Presumebly indicate his death.) now as a ghost in present he haunting the abandoned subway of newbury city and would do anything to scare or kill any trespasser that dares to step in the subway.

This take place to episode 4 called "Oh Rats!" of season 2 of lego hidden side while "Jack" and "Parker" were trying to break their ghost hunting tie, Rat €haun appeared and tricked them to go through separate tunnels. He got the army rats to surround "Parker" and "Cornelius".