Humans are too diverse to have evolved naturally. You look at dogs, and the sheer hundreds of lifespans it takes to get the different breeds, with their different temperments, and then one mongrel runs wild, and it undoes the whole thing. If humans evolved, they'd all have the same values, appearance, and mindset. Only the fact they were created by God 6000 years ago can explain how different everyone is, getting along, but not becoming just one phenotype.

There you go, if they argue in favor of Creationism, win. If they argue in favor of evolution, you just confirm humans are indeed like dog breeds and immediately end the conversation with the note that it's a good thing pit bulls aren't responsible for a disproportionate amount of dog attacks due to their natures, because that would imply something about humans.