He is shown to have a bad temper and get frightened easily.
Decka was kidnapped and put in a cage by Mayor Coleman so he could have an endless supply of gold, but when Mayor Coleman fed him meat he transformed into his primal form in which caused him to eat everything in sight. Echo Echo defeated him by letting him eat his duplicates, which are made of silicon. This caused Decka to vomit, expelling everything he ate and reverting him back to his normal state.
After he returned to normal, he says that he will never again return to Earth and will tell the others so they won't come back either, much to the mayor's greed.
Ben 10: Alien Force
- Fool's Gold (first appearance)