Wilbur would be selling mule bits, but everytime someone has bought mule bits, (which is food) people have heard a child crying. He also has been acting weird- you got a good glimpse of the child, they looked like the missing kid, Tubbo.

"Mule bits! Buy some mule bits!! Mule bits for sale!" He yelled out loud. A line would be formed He would then go into the back and yell and you swear you could have heard a Mule die.. you weren't Intrested in buying them of course so you just would continue on living and see people eating parts of a mule