Gargantua and Pantagruel
In François Rabelais' Gargantua and Pantagruel, medlars play a role in the origin of giants, including the eponymous characters. After Cain killed Abel, the blood of the just saturated the Earth, causing enormous medlars to grow. Humans who ate these medlars grew to great proportions. Those whose bodies grew longer became giants, and were the ancestors of Gargantua and Pantagruel.