Raxacoricofallapatorians are large, bulky humanoids that measure up to 2.5 metres tall. They are well adapted to their homeworld, with large eyes for seeing through the blizzards of the poles and powerful arms to swim through the oceans. They have thick, lumpy skin, ranging in colour from a yellowish green, a paler, grey-green or a brownish orange.
Raxacoricofallapatorians hatch from large green eggs with several tendrils and break out of these eggs using their powerful claws. By the age of 12, Raxacoricofallapatorians are still considered children and are shorter than a Human of equivalent age. Raxacoricofallapatorians had a great instinct to hunt, and would use their strength and poison-tipped claws to kill their prey. Their original prey were the baaraddelskelliumfatrexius beasts, which later became extinct due to overhunting. Despite their large bulk, they were also capable of surprising speeds and could easily overpower a Human. Raxacoricofallapatorians hunt by scent and can identify an individual's species, age, sex, emotional state and location by it. This sense of smell was officially the best in the galaxy. They could also sense the pain of closely related individuals from far away.
This ability to sense the pain of other individuals may have been partially telepathic, since it was shown to work across planets.
Raxacoricofallapatorians are calcium-based lifeforms, as opposed to the more common carbon and silicon based life. Due to their biochemistry, Raxacoricofallapatorians were vulnerable to acetic acid and would react explosively with it, a feature that was utilised in the Raxacoricofallapatorian death penalty.
Raxacoricofallapatorians had a more efficient metabolism than a Human, meaning they only needed to eat every few weeks and produced less waste. Raxacoricofallapatorian blood was red and their tears were milky in colour and slightly acidic. The females of the species could create poison when in danger, released either by a dart-like claw or through their breath.
The Raxacoricofallapatorians are a scavenger species, known for stealing advanced technology from other species. They are more advanced than Humans and had developed faster-than-light travel in the form of slipstream engines sometime prior to 2006. They could also modify a pig into a humanoid form using their own technology. Some of the Raxacoricofallapatorian technology appeared organic in nature. While in Justicia, Ecktosa and Dram used sticky nets as hammocks. These nettings were covered in a slime that quickly hardened away from body heat. Other Raxacoricofallapatorian buildings had their floors covered in a sticky substance.
The Raxacoricofallapatorians' most distinguishable technology was their compression field. The Slitheen and Blathereen families were able to disguise themselves as other, smaller humanoids by fitting into their skin suits. This was done with the compression-field collars that they wore on their necks. When unzipped, pent-up energy was released through the zip in the form of a flickering blue light. Their size was controlled by the movement of gas, which caused a condition similar to flatulence, but with a smell slightly similar to that of rotten teeth (due to their calcium-based biology). These individuals originally needed to be large, but the advancement of technology meant smaller skins could be used. These skin suits were apparently inferior to those of other species.
The Raxacoricofallapatorians mastered the concept of string theory .
Raxacoricofallapatorian society was based off families, such as those of the Slitheen, Blathereen, Slitheen-Blathereen, Slavereen, Caizeen, Lilieen, Rackateen, Chippeen, Fittereen, Hanazeen, Glizeen, Hostrozeen and Arlene. Raxacoricofallapatorian names are complex, with the various hyphenation showing their exact placement on the family lines. Raxacoricofallapatorians were led by a Grand Council and an Assembly. The leader of this Council was the Lord Predator.
The Raxacoricofallapatorians had the death sentence for dangerous criminals like the Slitheens, which was carried out in a gruesome way. The criminal would lowered into a cauldron of acetic acid, which would then be heated to boiling. The acidity of the solution was formulated to dissolve the skin, allowing the internal organs to drop into the liquid while the condemned was still alive, resulting in a slow and painful death.
Raxacoricofallapatorians neither brushed their teeth nor prepared their food in complicated ways.
Two known Raxacoricofallapatorians insults were "May plaque brown your belly" and "May your mother boil in the cauldron of atonement." Both were presumably related to their calcium-based biology.
Raxacoricofallapatorians are part of the four-world Raxas Alliance along with the Clomians and the people of Raxacoricovarlonpatorius and Clix.
Most Raxacoricofallapatorian criminal families were descended from the Huspick Degenerate.
Sometime before the 21st century the criminal Slitheen family bribed their way into power on Raxacoricofallapatorius. Their rule crashed the planet's economy and eventually the population rose up against them. Exposed, shamed, and arrested in the Great Purge of Yon:556, the entire family was tried and found guilty with no chance of appeal and given the death sentence. Many of the Slitheen fled justice, but the family continued to be hunted down by the Blathereen family and the Judoon. The actions of the Slitheen ruined the good name of the Raxacoricofallapatorians.
Following this, in March 2006 they disguised themselves as various Humans holding leadership positions and attempted to seize control of the English government in an effort to start a nuclear war. Their ultimate aim was to turn Earth into a huge nuclear reactor pile and sell its remains off as starship fuel. This attempt was foiled by the Doctor and his allies.
In the 347th century, Raxacoricofallapatorians fought in the Platonic War, alongside various other alien races, against the Human race.
In the year 34,600, the Lord Predator was Haralto Wong Bopz Wim-Waldon Arlene, however he died shortly after this.