Externally, they look like large crustaceans with a jointed carapace, red eyes, white mandibles and three pairs of limbs (four clawed arms and two legs), and need humid environments to develop. Inside the carapace, the inner body of the Skraaldian looks like a massive pale slug with jointed antennae, white eyes and numerous reddish tendrils surrounding the mouth, which can be used to strangle opponents in a fight. While the crustaceanoid armor is assumed to be their true form, they are known to conceal themselves in presumably artificial exoskeletons with different appearances, made to resemble other species. They are also able to crowd a single human-sized shell with as much as seven Skraaldians inside, likely confirming that they have no skeleton or hard parts of any sort.
The Skraaldians are venomous creatures, their bite causing victims to swell and turn deep red in color, although the symptoms only last for a week. They are also known to spit white ink, possibly as a defense mechanism.
The Skraaldians consider showing one's nasal mucus the worst possible offense (far worse than killing one or even two of their own). They punish those who offended them by throwing them in a boiling liquid known as the Soup. Skraaldians are known to use insectoid vessels shaped vaguely similar to their individual exoskeletons.