This is a theory made by my friend from Wattpad, MetalSmasherNTT and this is a theory of how Michael Theodore became an exact double of Mickey Mouse, which will explain to you of how this all happened to him after he injected himself with the syringe filled with the drug and ink inside that turned him into what he is today.

All credit to this theory belongs to . Not me.

Well, it comes from Bendy.

You see I believe Joey Drew was based off of Mark Fleicher, a Rival animator to Walt Disney.

Walt basically took credit for a lot of Mark's creations. 

In fact Mickey's design was ripped off from one of Mark's characters Bimbo the Dog. 

There's a lot there that I can't explain properly, so I won't.

But basically Mark died mostly forgotten while Walt's legacy lived on.

Mark was obsessed with making cartoons more real and maybe in this universe he succeeded but died before he could reveal this amazing creation.

When Walt repossessed all his things, his studio, his ideas, everything maybe he found this ink and it's formula which helped him bring Mickey and the others to life.

However the ink was never meant to be used on a person which is why it transformed Michael.

Also I like to think the ink doesn't randomly transform you into any character.

I think it transforms you into the characters you resonate with most, like before Michael met Mickey maybe he liked Mickey's cartoons the most, maybe those cartoons were what helped him through some of the tougher times in his young life.