Here's what I thought was going to happen when I saw molten aluminium get poured into a watermelon: it would explode, it would destroy the melon, it would eviscerate the flesh, it would burn everything in site, it would be stupid, but it would be fun, because watermelons are fun to destroy. But here's what actually happened.
The molten aluminium snaked its way through the watermelon and found the seed patterns and open channels and basically casted a mini watermelon seed tree of itself. I guess I should have expected that! Since it's not unlike when you pour molten aluminium inside an ant hill.