The Yolkians are a race of "yolk"-like aliens who rely heavily on egg-shaped anti-gravity suits for moving from place to place. Their characteristics are similar to humans. They worshiped what they believed to be their goddess, a giant chicken monster named Poultra before Jimmy stopped them from feeding his loved ones to her.
Yolkians have slimy green skin, which turns white to exposure of heat. They have a lower percentage of water inside their bodies, and they don't socialize with carbon life forms. The race is so advanced that they have found no need for their original bodies; instead, they rely on egg-like structures to hold their bodies in.
In Jimmy Neutron: Boy Genius, Jimmy said that the aliens were advanced species, since they had no need for their original bodies. Sheen said in reply that his boogers look like an "advanced species", to which Cindy and Libby grossed out and said together, "Ewwwwww!".
The Yolkians live in monarchy under the rein of King Goobot. They've tried for countless millennia to find sufficient sacrifices for their god Poultra. A couple minor, normal Yolkians made cameo appearances in "Win, Lose and Kaboom" and "Jimmy Timmy Power Hour 3: The Jerkinators!".
Yolkians travel by giant metal roosters. Their egg-shaped suits have the capability, they will use it. Their women are dressed in the most elegant of bacon silk dress wear,
In "The Eggpire Strikes Back," they dropped their suits to fill up a huge egg-shaped spaceship.
The Yolkians primarily use metal spears with electric points, which can be used to numb their opponents. It's later revealed that these spears also can release an electric blast at long distance targets; however, they're either too arrogant or too stupid to this feature often.
- When King Goobot's guards attack in one of the final moments of the movie, Jimmy yells out that they are Carbon Based Lifeforms.
- The fact that they use chicken-like spaceships for transportation, makes sense since everything is almost chicken related. From egg shaped bodies, ships and even certain "God " that they worship that comes out of an egg shell.