He is implied to be mentally unstable, stuttering constantly whenever he speaks and mumbling to himself.
April Fools Event
In the April Fool's event of 2020 (April 1, 2020), Burt bought a lot of pet rocks then tried to sell them, but after numerous unsuccessful attempts, he made the rocks free. This event only existed for a few days and the Pet Rock was removed right after. The pet rock was always full-grown and also had fly and ride abilities.
Dress Your Pets Live Event
Burt made another appearance In the "⛵??????⛵" update, where he appeared to be fishing behind the Hospital. His hook lead to a sunken boat which would later become the Hat Shop. There players could find three parts of a Key, which could unlock a vault located in the center of the Pet Shop, which contained a crown pet accessory, the first accessory that was ever made available to players. 7 days later, Burt fished out the boat in what was Adopt Me's first and currently only live event, the Dress Your Pets Live Event. After the event, the aforementioned key turned into a throw toy and was renamed "Founder's Key Throw Toy", and it could no longer open the vault in the Pet Shop.