WMG / The Curse of the Were-Rabbit

Victor thinks that “Pesto” is Wallace's surname.

Lady Tottington referred to Wallace as “Mr. Wallace” before she knew him on a less formal basis. Whenever Victor addresses Wallace, he uses “Pesto” as if it’s a surname (e.g. “I know your little secret, Pesto!” or “You can hop, but you can’t hide, Pesto!”). It’s possible that Victor believes that Wallace used his name as a pun for his business.