Yeah, us neither, but the video is pretty cool!
(The electrifying of the watermelon happens closer to the 3 minute mark!)
What happens when you pump 20,000 joules into a watermelon? Two words. Pink Mist. After trying to blow up a watermelon with a smaller capacitor, my friend coyt brought over 4 capacitors rated at 20kv and 25uf each.