What happens when you put 20,000 volts into a Watermelon?

What happens when you pump 20,000 joules into a watermelon?

After trying to blow up a watermelon with a smaller capacitor, Backyard Scientist Kevin Kohler brought in his friend Coyt with 4 capacitors rated at 20kv and 25uf each. The components came from a lab that used to them to simulate the effects of lightning on materials.

To rephrase the original question: So what would happen if a lightning bolt struck a watermelon!