Squirmgrub is a Warrior Librarian who first appeared in the novel, Lightning Rod Faces the Cyclops Queen. He was one of Wiggleworth's most trusted librarians, and was assigned to help the Skylanders guard the fragments to the Mask of Power. However, he was secretly working for Kaos and acted as his double agent to help pass the locations of the fragments of the Mask of Power to him.
Squirmgrub was willing to help the Skylanders on their quest to retrieve the fragments Mask of Power, but does so in order to pass information about the fragments' whereabouts to Kaos. His shiftyness and sneaky demeanor however, doesn't come unnoticed by the Skylanders.
Lightning Rod Faces the Cyclops Queen
Squirmgrub travelled with Hugo, Flynn and Double Trouble to the Storm Giant Games by Flynn's hot air balloon to inform Master Eon of the location of the Air segment to the Mask of Power. However Lightning Rod accidentally hurled a large hammer in the path of Flynn's balloon, causing it to spiral out of the control. The Skylanders quickly came to the rescue, knocking away the balloon's dangerous debris from the spectators within the stadium and saving Flynn, Double Trouble, Hugo and Squirmgrub from crashing. When the Skylanders retrieved the Air segment to the Mask, Squirmgrub retreated to a secluded area of the Eternal Archive and contacted Kaos via crystal ball, revealing that he is a spy for the evil Portal Master and would later inform him of future locations to the Mask of Power.
Terrafin Battles the Boom Brothers
Without Master Eon's notice, Squirmgrub had found the next location to where the Earth segment to the Mask of Power laid, but didn't report the discovery to the Skylanders. Instead he had shared the information with Kaos. After the Skylanders' scuffle at the Fantastic Fairy Fair, Squirmgrub hid the book that contained information on the exact whereabouts of the Boom Brothers, but Master Eon and the Skylanders were able to find it. Although Eon and Terrafin knew that the Librarian's actions were intentional, the old Portal Master believed it was an "honest mistake". Squirmgrub then informed Kaos that the Skylanders were on their way to the Explosive Emporium.
Cynder Confronts the Weather Wizard
The Warrior Librarian helped Master Eon, Cynder, Hex and Zook in locating the next fragment to the Mask of Power after getting reports of unusual weather conditions throughout Skylands. While the three Skylanders went to the Isle of the Dead, Squirmgrab kidnapped Master Eon and stole five segments to the Mask of Power with him for Kaos, an action that ultimately unveiled the Skylanders the Librarian's secret allegiance to the evil Portal Master.
Stump Smash Crosses the Bone Dragon
Squirmgrub, Kaos, and Master Eon were turned to stone by the enraged Bone Dragon when Kaos intentionally aroused the creature from his slumber. Eventually, the Skylanders were able to calm the Bone Dragon and convinced him to turn everyone back to normal, including Squirmgrub. However being turned to stone was all part of Kaos's plan to get the Life segment of the Mask of Power, and the evil Portal Master began blasting at the Skylanders with his dark magic. Upon being revived, Master Eon quickly stopped Kaos's assault and casted a spell on Squirmgrub that shattered the Librarian's robot suit. This left Squirmgrub defenseless as punishment for his treachery. When Kaos was defeated and the Life segment was obtained by the Skylanders, Squirmgrub was left behind by Kaos. Spyro easily seized the traitorous Warrior Librarian worm and took him back to Chief Curator Wiggleworth so that he could "have a word" with Squirmgrub.