Gumball, Darwin and Anais discover that Mr. Wilson has been picking on Richard for most of his life; ever since he humiliated Richard with a high school prank. The kids try to work Dad through it but when their efforts fail, they realize that getting back at Mr. Wilson is the only way to break the cycle.
This is Harold's second major role in the series. His first was in "The Bus."
One of the pictures on the lockers in Richard's flashback is the propaganda poster from "The Vision," featuring Hector.
Richard mocks Anais for reminding not to forget his appointment at the cardiologist, like how he mocked Nicole for reminding him in the episode "The Limit."
When Anais inserts her specialized Daisy the Donkey dollar bill into the lawyer's box, the music that plays sounds similar to that of "The Candy Mountain Cave" song from the Youtube series, Charlie the Unicorn.
The Daisy dollar that is used for Daisyland is a direct reference to the Disney dollars used as currency for the Disney parks and Disney stores.
Harold's behavior towards Richard seems to contradict previous, more passive reactions between the two characters, with the two even working together as equals in "The Bus."
However, it can be assumed that they simply had a common goal in that particular episode.
The poster featuring Hector shouldn't appear in Richard's flashback as it takes place long before "The Vision" and was imagined by Gumball and Darwin in the first place.
When the spotlight is on Richard, Mr. Corneille can be seen in the corner without pixellation. When it shows Harold laughing, though, Mr. Corneille is back to normal.