They are enormous worm-like Grimm capable of burrowing underground and through the sands of Vacuo. They have a singular red eye and a giant fanged mouth. These Worms can range from 6 feet to bigger than Flatback Sliders, which tower at over 100 feet in height, and are built to be far faster when traveling in sands. Like the King Taijitu, they have a head on each end of their body
Their defenses include bone plates, hooks and acidic blood. They attack with spiked teeth and are capable of spitting acid.
Coco Adel speculates the reason the Blind Worm was given its name is due to the fact it tends to use blindsiding tactics when attacking, and its insides are pitch black.
In After the Fall, Team CFVY encounters a giant, ancient Blind Worm, which attacks the Huntsmen as well as travelers from the nomadic tribe of Feldspar that was traveling to Coquina atop a flatback slider. There, Coco Adel and Velvet Scarlatina battle the Grimm, where it temporarily swallows Coco whole until she breaks free of it from within.
After being injured, the Grimm makes a temporary retreat, later making a return at the last chapter of the novel, where it nearly kills all of Team CFVY before being killed itself by Team SSSN.
A nest of Blind Worms killed one-third of Octavia Ember's clan when she was a child after they had been caught in a sandstorm.