Yugopotamia is almost the complete opposite of Earth. Everything Earthlings love, they hate, and vice versa. Chocolate is poisonous to them, hugs burn them and they are afraid of things that are happy, healthy and fun. Although the Yugopotamians can be considered war-like people, however due to them creating weapons out of things that they don't know aren't harmful to species outside of themselves (I.E. bombs made of candy), they are of little danger to the people of Earth. By that same token however, other more dangerous aliens have been known to threaten the Yugopotamians, such as The Gigglepies, Bodacians, and The Darkness. One running gag is that most people from Earth who have been told about Yugopotamia call it 'Europe'. Yugopotamia is exactly 1,000,000,001,000,000 miles away from Earth, shown when Timmy wanted to send Vicky a million million miles away and Yugopotamia happens to be "one million, one million," as stated by Cosmo in Totally Spaced Out.
Yugopotamia and its inhabitants were first introduced in the episode "Spaced Out", when Timmy wished for an alien monster to play with. Timmy noted that the alien was so lifelike. It turned out to be real, because Cosmo and Wanda and not so good at creating aliens, so they borrowed one. Yugopotamia appeared when Queen Jipjorrulac was wondering where her son was.
Yugopotamia celebrates F.L.A.R.G. every year, but they celebrate it on a planet other than theirs due to the last day of F.L.A.R.G. involving them blowing up the planet they celebrate F.L.A.R.G. on (hence why it is celebrated on somewhere else other than Yugopotamia).
Yugopotamians have a bomb located in their bodies that are activated depending on the celebration of F.L.A.R.G.; If the holiday is not celebrated completely, the bombs go off. After F.L.A.R.G.'s celebration is completed, the bombs defuse themselves.
Yugopotamia was destroyed by the Darkness, but was restored after the events of Wishology since it is okay in the Season 7 episode "Planet Poof".
Yugopotamia may have obtained the "Yugo" (serbian "south") from the former country of Yugoslavia, which happens to be in Europe. This may be why people (often Vicky) sometimes called it Europe.
The name of Yugopotamia came maybe from Mesopotamia, which is the first civilization on Earth.