Agatha's Wasp Eater, unofficially nicknamed Honker by some in the fandom, is a weasel-like creature which Agatha Heterodyne acquires after Tarvek Sturmvoraus rescues the surviving wasp eaters and the human members of the Vespiary Squad from Wulfenbach forces. The name "Honker" comes from the he makes when he adopts Agatha.
It accompanies her through the portal beneath the Cathedral and emerges with her two and a half years later. When Martellus von Blitzengaard alters Agatha's body chemistry to cause her to and (according to Martellus) eventually die without an occasional physical touch from him, Agatha to allow it to substitute for the would-be Storm King, subverting his attempt to exert control over her. Later, after Martellus discovers this circumvention, , only to be by Violetta's impossible thieving skills. After being separated momentarily during the flight from the secret base of the Knights of Jove, with Agatha in the secret refugee camp where the Jägers and displaced Mechanicsburg townspeople are residing, showing that Agatha is still physically dependent on it at this time.
Later Agatha's Wasp eater accompanies her on a ride on the Corbettite Railway to St. Szpac and then to Paris. Agatha is still very protective of her wasp eater, asking help from Violetta to safeguard it from Martellus in the vaults of St. Szpac and deploying her Dingbots to prevent it from being grabbed by Madame Desmana in a shop in the Parisian Black Market. It is not clear whether this is because she still needs regular contact with the weasel to survive, or "merely" because it may be the last of its kind alive, and its revenant-detecting abilities are invaluable in the face of The Other's return. This second value prompts Agatha to make a deal with Desmana to let the latter be an authorized seller of the Weasel's technical specs to anyone willing to pay for them (especially Gil), in the hopes of jump-starting the creation of more of the creatures.
Agatha's weasel uncovers an extensive infestation of sleeper revenants in the Arguron Palace, where it is revealed that their king is in league with The Other. It is targeted by the host of revenants in the ensuing melee. After it escapes the Arguron Palace and arrives at The Incorruptible Republic of the Immortal Library of the Grand Architect, it is presented as proof of the veracity of the monograph that Agatha wrote on wasp eater science. It accompanies Agatha and company on sojourns throughout the Library, such as into another Corbettite hazard vault.
Honker seems to take his death defying adventures with Agatha as great fun.