So, people have been accustomed to mythical beings such as the Basilisk and Medusa, turning people to stone and such. This concept, however, has rarely appeared in sci-fi.
Until I came across the Laundry Files, with their weapon concept called the Scorpion Stare, which works like this:
"One of the weapons Her Majesty’s Government is developing to deal with the threat is the SCORPION STARE network. Two or more observing viewpoints—cameras—feeding the right kind of hardware/software network can, shall we say, impose their own viewpoint on whatever they’re looking at. In the case of SCORPION STARE, about ten percent of the carbon nuclei in the target are randomly transformed into silicon nuclei as if by magic. Messy pyrotechnics ensue: gamma radiation, short-lived muons, some really pretty high-energy chemistry, and lots of heat. We worked out how to do it by reverse-engineering basilisks and medusae—animals and unfortunate people suffering from a peculiar, and very rare, brain tumor. Now we’ve got defensive camera-emplacements on every high street, networked and ready to be controlled centrally when the balloon goes up. Street cleaning by CCTV-controlled flame thrower."
So, while transmutation is obviously handwavium, in reality, such transmutations are plausible with Carbon and Oxygen Burning Fusion, where they fuse to form things such as Magnesium, Sodium, Silicon and Sulfur.
The catch? Such would require extremely high temperatures, between 5 × 10^8 K and 10^9 K.
Is it possible to create a beam that operates at such high temperatures?
Here are my rules:
- Assume that there is minor unobtainium, a material that can withstand such heat in the first place, to construct the weapon.
- The weapon can be of any size, need not be camera-sized.