Bully Bill is an antagonist of the SuperMarioLogan franchise. He is a young Bullet Bill with a large tendency to bully other characters, especially and mainly Jeffy.
Why He's Intentionally a Mean Bully Indeed
He is completely one-dimensional and moronically so, he seems to never learn his lesson about bullying Jeffy. He's been beaten up (and even killed) on many occasions, yet still decides to bully him, which shows that he simply doesn't know any better.
His motive for bullying people is not good at all. The reason he bullies people over and over again is because... his name is Bully Bill, which is just very poor writing.
He is an ableist as he often uses the word "retard".
He uses the word "retard" as an insult towards Jeffy. This may have made sense in 2016-2017, but Jeffy seems to have matured over time and become a bit smarter, yet he still used it towards him.
His character is a rehash of Tanner from the Bowser Junior's Summer School series. The only difference is that Tanner is well-executed, while Bully Bill isn't.
He also seems to be pretty stupid. Aside from Bully Bill's acts of stupidity that always end up getting him beat up by Jeffy because of provoking him, he often confuses other characters by posing to be Jeffy as Jeffy himself. Some notable examples include:
In "Robot Jeffy", he confuses Jeffo for Jeffy when he tries calling for him then gets into a fit of rage and hits Jeffo, which is very idiotic of him when he got Jeffo to go on kill-mode to disintegrate himself, destroy a plate and try to kill everyone including Mario, Junior, and Cody.
In "Jeffy's Lunch Money", he didn't see that Black Yoshi dressed up as Jeffy and still thought it was the latter despite calling him a doofus for making Jackie Chu enraged by Black Yoshi's idiocy (although to be fair; almost everyone, except for Brooklyn T. Guy, was just as dumb to think that Black Yoshi dressed up as Jeffy was still Jeffy),