Osquip
Osquips are a weird species of rat-like monster originating from the early days of Dungeons & Dragons, resembling a dog-sized, many-legged, hairless rat with oversized, stone-crushing teeth. They are sometimes used as familiars by wizards, since their dung is an acceptable reagent in various spells related to manipulating earth, they are quite loyal, and their bite is devastatingly powerful. They are also sometimes reared by jermlaine as guardians and steeds.
First debuting in the Fiend Folio for Advanced Dungeons & Dragons 1st edition, they were updated to 2nd edition in the Monstrous Compendium Volume 2, before being printed in the Monstrous Manual under the heading "Mammal, Rat". They received an "Ecology of the Osquip" article in Dragon Magazine #227, which was the debut of the Monster Hunters Association as well, and were updated to Dungeons & Dragons 3rd Edition in Dragon #267, before formally debuting for that edition in the Races of Faerun splatbook for the Forgotten Realms.