Insects are a recurring theme in the Magnus Archives, from the infamous Jane Prentiss to the spiders and ants.
Worms & The Flesh Hive
Jane Prentiss was once human, but over the years became host to a huge hive of worms and became known as The Flesh Hive. The worms are around an inch long, with silver segmented bodies and blackened heads. She seems to have infected Harriet Lee (MAG 6) who passed the infection into Timothy Hodge (MAG 26), who was later killed by Sasha. Although Jane Prentiss is now dead (MAG 40), the scars she caused, both physical and mental, remain.
The worms of the Flesh Hive seem to be conscious, or at least are able to burrow their way down into the basements of the Archives.
Spiders have appeared in many cases of the Institute. Carlos Vittery was plagued by a seemingly immortal spider that he crushed when he was a child (MAG 16), and was likely killed later by a group of spiders.
Alice "Daisy" Tonner had a story that she didn't tell about looking into spider-husks, which may have been human sized, or humans that were spider husks (MAG 43). It is possible that this is related to an entity that Trevor Herbert discovered (MAG 56).
Good Energies, the crystal shop that Jane Prentiss worked in, was closed down due to an ant infection (MAG 32).
Jordan Kennedy was called to a house infected with ants which seemed to originate from a fridge. Before he was able to tackle it, the owner of the house attacked him. After almost being strangled, Jordan set the man on fire (MAG 55).