[url=https://www.youtube.com/watch?v=CeAP1WiO1Dk]Oxy-lance[/url].

[url=https://www.youtube.com/watch?v=hpJS_skyFvg]It's a thing that can and has been scaled-up.[/url]


It has obvious limits, though.
-Mostly in that it was designed for scrapping/maintenance applications.

However, unlike a plasma-cutter, it does not need the opponent's compliance.
*It's pretty much a thermite-powered flamethrower, and will cut wood and concrete just fine.