At least some content in this article is derived from information featured in Fantastic Beasts: Cases from the Wizarding World. Spoilers will be present within the article.
In a beast-related incident investigated by Mathilda Grimblehawk and her partner from the Ministry of Magic's Beast Division, Chivers was reported to be missing. He was later found unconscious in the London sewers having been knocked out by falling bricks. He was then transported to St Mungo's Hospital for Magical Maladies and Injuries and treated by Healer Omar Abasi.
Chivers believed that the British Ministry of Magic was involved with covering up the existence of Nargles. He went to Slug & Jiggers Apothecary hoping to purchase Narglecide, so Humphrey Balsamo relabeled some dud potions, and gave them to him free. These potions included an unstable Swelling Solution which was consumed by the beast dwelling in the sewers.