The Delightfulization Chamber is a machine designed and owned by Father and an object in Codename: Kids Next Door. It permanently transforms any child into a "perfectly-behaved" zombie version of themselves and they are rendered absolutely loyal to all adults.
It was created by Father, who used the first prototype on KND members Sector Z.
The unstable machine had a even more powerful effect by about eleventy billion-fold than a "normal" one, creating the Delightful Children From Down the Lane, but destroyed the chamber in the process.
Afterwords, only less powerful versions of the machine are seen in the series.
Delightfulization Chambers are only seen in Operation: B.U.T.T. and The Grim Adventures of the KND. In the latter, Billy while he was wearing his dad's "lucky pants" and carrying the Grim Reaper's scythe was conducted to delightfulization, resulting in the creation of the Delightful Reaper.