Omicronians are overtly belligerent, and they possess a proclivity for waging wars over seemingly petty matters.
For example, in 1999 a FOX television station was knocked out during the season finale of "Single Female Lawyer". The Omicronians in the year 3000 enjoyed watching the show, which was broadcasted on Omicron Persei 8 via television signals originating from Earth, but were enraged when the show surceased abruptly during a climactic scene. They subsequently invaded Earth and demanded to see the ending of the show, and if it wasn't for Philip J. Fry's expertise in television programing, they would have laid Earth's cities to waste with their anti-monument lasers.
In a parallel universe in which life was more like video games, the Omicronians headed a force of Invaders (possibly from space) that defeated Earth's defense forces to demand the planet's quarters so that they could do their laundry.
The Omicronians mating process can be dangerous to bystanders, and it is highly recommended that one stays outside a 500 meter radius during the process. Once born, the Omicronian raise their young, which resemble fried shrimp, by depositing millions of them into large pits on nursery planets (though they watch over them from a distance with security cameras). When their young grow up, they eat their mothers.
They have great strength and durability and are more technologically advanced than humans. Their mouths are big enough to swallow adult humans whole.
Relations with Earthicans
Omicronians have an interesting relationship with the planet Earth. On several occasions the Omicronians have invaded Earth for a variety of reasons, and they don't understand the Earthican cultural norms such as chalky-valentine hearts.
Despite this, they seem to have a great affinity for other aspects of human pop culture enjoying Earth sitcoms that many humans don't particularly like, apparently because they can relate to the characters. This is particularly interesting because Omicronians are unable to distinguish between humans, or even the various primates native to Earth.
This appears to be the case even after it was discovered that the Earthicans had eaten over 198 billion of their young: After the Planet Express Crew came across a nursery planet, they brought back shiploads of what they assumed were simply delicious snacks, and sold them through Fishy Joe's as Popplers. 
- "When Aliens Attack"
- "The Problem With Popplers"
- "Anthology of Interest II"
- "Love And Rocket"
- "Spanish Fry"
- "Lrrreconcilable Ndndifferences"
Most Omicronians appear to be named based on their occupation; namely those that have the suffix "er". The first letter of their name is the first letter of their occupation, and the last 3 are "rrr". For example, Drrr is a "Doctor", Lrrr is the "Leader" of Persei 8, and Jrrr is a "Junior".