Yeah that lightning to glass thing cracked me up.
Stick the rebar in the beach and then, bam...instant Waterford crystal.
The reality is somewhat different. In south central CO there is a sand dunes national monument. They have the real thing on display. The glass structures are interesting looking but they are not nor would they ever be anything like that movie was suggesting. For one thing you can't see the glass because the whole thing is covered in sand. And that's because when the sand is flash fused into molten glass it's still surrounded by sand which, of course, sticks to it.
As far as the ants are concerned I would be totally good with pouring liquid metal into every single fire ant mound in existence.