I completely changed Circus spider's Lizard design and story a bit too
Attempting to cure an sickness he seemed to be losing, desperate for a solution and through his extensive reading he thought he had found it. He bound himself to a lizard like being that had healing properties, and it worked, sort of. It did help him recover from his illness to a degree, leaving the symptoms a lot more bearable, he just would have to take the form now and again for him to recover when it got bad again. Eventually someone caught on to the beast that he turned into and captured him selling and he was alter sold to the circus as an impressive monster. In order to take advantage of the intimidating looking form they kept him in a perpetual state of stress through various violent means. These acts were a secret among the section of the circus that handled beasts.
Spider be friended Lizard in the circus by chattering to him, Lizard eventually felt at ease enough that his body let him shift back into his human state.
Circus Spider did not have the key to Lizard’s cage. Circus Spider frantically ripped the bars panicked and trying to free the man who was now standing where lizard once had. Circus Spider then kind of panicked about having done that and the scolding they were going to get and Lizard absconded while they were panicking.
The other circus folk never in the end learned that Circus Spider was the one who broke the bars and just assumed it was Lizard who had broken free because it made a lot more sense a giant lizard monster broke itself out of the cage rather than some kid ripping the bars away bare handed.
ID:
Image One: Four Illustration of OP's design for Lizard. He is tall, gangly with a long neck and lanky limbs and has a lizard mask over his face that lists over like a mount with teeth showing no face underneath.
Image two: A diagram showing how the mask comes out of Lizards fore head and covers his face when he transforms and another drawing of Lizard sitting with an arched back and open mouth presumably hissing
Image four: An illustration of Circus spider standing outside of the cage Lizard is standing in, chatting away to him -ID End)