The toad, a mundane yet magical creature, serves as a fruitful focal point for exploring the evolution of witchcraft beliefs and its prosecution in Spanish Navarre. Drawing from local, non-inquisitorial witch trials in Navarre, this article reveals how toads evolved throughout the sixteenth and seventeenth centuries, and demonstrates that villagers, jurists, and inquisitors alike considered toads as significant evidence of witchcraft. The toad in Navarre was the witch’s accomplice and purveyor of her poison until its ultimate metamorphosis into the witch’s familiar in the imagination of Spanish inquisitors as they reinterpreted local lore within their learned demonological frameworks. No longer merely used in maleficia, toads actively helped orchestrate it. This paper argues that witchcraft beliefs, prosecutions, and demonologies were an adapted, negotiated, and shared cultural production.