For hundreds of years, women in several countries would leave "toad votives," candles shaped like toads, at Christian sites and shrines. The symbolism of the toad has to do with childbirth. And the reasons for that association are both numerous and weird.
In the medieval world, toads were charter members of the cabal of slimy, devilish creatures imbued with powers and beloved of witches—tormentors of the sinful mind. In one medieval church sculpture motif, the femme aux serpents, the embodiment of sinful lust, toads sometimes sub in for the snakes that writhe around a woman’s body and occasionally bite her breasts. But toads weren’t as purely evil as snakes; they could be humorous, too. In one German story, a woman loses her vagina and it “is mistaken for a toad as it roams the streets,” writes Blumenfeld-Kosinski. (Eventually, the woman gets her detachable vagina back.) Toads were also thought to have the power of spontaneous generation and resurrection.
Even weirder is the association of the toad votives with toad votive, who is more of a legend than a saint. Read how a miracle saved Wilgefortis from an unwanted marriage at Atlas Obscura. That she became a patron saint of the marital bed is just more weirdness.