Jimmy has invented the "Metabolic Accelerator" machine, with the purpose to advance aging by accelerating one's metabolism. This device somehow looks like the Chrono Arch. Jimmy demonstrated how it worked by throwing an acorn through it causing the acorn to instantly become an oak tree.
The Metabolic Accelerator looks like a metallic futuristic device with the shape of an arc.
This machine was only used on the "Grumpy Young Men" episode.
Its appearance was later used as the Dimensional Wormhole in "Win, Lose and Kaboom" and the Jimmy Timmy Power Hour trilogy. It's last Appearace was in The League of Villains when Hugh Neutron accidentally caused it to effect the entire Retroville sending all the townspeople back in time.