kaddlehopper
A dumb country bumpkin who takes every joke like it's a promise, even when it's a joke about your mom and your dog.
My uncle is a kaddlehopper. He thought the guy who sold him a fake treasure map was telling the truth, and now he's digging holes in his backyard.
My friend is a kaddlehopper. He believed the conspiracy theory that the government is making him eat cereal for breakfast.
My brother is a kaddlehopper. He said he'd stop eating tacos if I promised him a pony, and now I'm out a pony and still eating tacos.