Faux Chapeau is the second part of the 4th Aired and 3rd produced episode of season 4, which first aired on May 9, 2003. In this episode, Dee Dee mistakes Dexter's latest invention for a hat and wears it around town. However, the invention later gives everyone, including Dee Dee, swelled heads.
After hard working in the lab, Dexter went outside to find some drinks. Only found out Dee Dee was selling his invention to people when he got back. Dee Dee then persuades Dexter the idea of selling them as hats. Since then, the hat business took off, and it’s getting bigger and bigger until eventually forming a large corporation. After a while, they found out the problem caused by this invention: since this invention is meant to magnify molecules, putting it on people's head will also made their head huge. Luckily, an ointment can help their customer’s head back to normal size, so he duplicates 50 million tube of ointment, and mails refunds to the customers. After the refund was completed, Dee Dee told Dexter she has sold Dexter's another invention that looks like shoes.