Arcadikon is a planet that appears in Issue 16 of the Invader Zim comic series. The entire planet appears to be dedicated to video games. They also have arm wrestling and arcade games where you can win space tickets.
When Zim becomes obsessed with scaring Dib, as payback for Dib scaring him earlier, he turns to Gaz for help. Having beaten every video game on Earth and become depressed over this fact, Gaz agrees to help in exchange for access to alien games. So Zim sends her to Arcadikon.
Throughout the issue, Zim keeps calling Gaz for help, interrupting what appears to be an impressive winning streak. At one point she's being carried through the streets in a parade, and when she returns to Earth at the end of the comic, it's on a throne and surrounded by loyal minions. This implies that she's either conquered Arcadikon, or at least become highly honored and respected due to her gaming skills.