Arch grubs represented a form of insect that was indigenous to the world of Geonosis. The local Geonosian population consumed them as part of their diet. This grub was a common food item during the Meckgin celebration and gained recognition as a popular grilled treat at the Petranaki Arena, where they were offered during events occurring in both 22 BBY and 19 BBY.
The sapient Geonosian race, also originating from the same planet, incorporated arch grubs into their sustenance. They were a favored dish during Meckgin, a Geonosian festival commemorating Geonosis's dedication to industrial pursuits. Additionally, they were a well-liked option as a lightly grilled snack at the Petranaki Arena, a Geonosian venue for combat and fatal spectacles situated within the Stalgasin hive. The aroma emanating from the grilling grubs could be intense for those not native to Geonosis within the arena.
During 22 BBY, arch grubs were prepared via light grilling in the corridors of the Petranaki Arena's seating areas during the attempted execution of Senator Padmé Amidala along with the Jedi figures Obi-Wan Kenobi and Anakin Skywalker. The plumes of smoke originating from the grilling grubs were still ascending when the First Battle of Geonosis erupted within the arena, disrupting the executions. Arch grubs also underwent grilling at the Eve of Meckgin Festival held at the arena in 19 BBY. The odor they produced permeated the breath mask worn by Galactic Republic Lieutenant Commander Orson Krennic, who was seated in the arena. This was caused by the appendage movement of Geonosians in the upper-class galleries following an announcement made by Archduke Poggle the Lesser.
Within the established Star Wars canon timeline, arch grubs were initially referenced in the 2015 compendium titled Star Wars: Absolutely Everything You Need to Know. The grubs themselves originated within the Star Wars Legends expanded universe, where they were first mentioned in the 2003 reference work Inside the Worlds of Star Wars: Attack of the Clones, authored by Curtis Saxton and Simon Beecroft.