What's the most difficult catalytic converter protector to cut?

Does anybody sell a heat tolerant paint on abrasive coating? I know there are paint on anti slip coatings, but I doubt they would stand up to the heat right next to a catalytic converter. In any case, the idea would be that any cutting tool blade/bit would be quickly ruined by the carbide (or whatever grit is used) in the abrasive coating.

 

Not sure how quickly, but faster than pure metal. I'm assuming the thieves use metal cutting blades, and those are not intended to rip through abrasives. There are sawzall blades for cutting concrete and other abrasive substances which wouldn't care about the coating, but they might not do so well on the metal then. The optimum "no cut" material would be some sort of repeating sandwich/honeycomb of metal parts filled with something like diamond dust embedded in concrete. There are research materials along these lines which are said to be nearly impossible to cut (without changing blades/wheels frequently), but I'm not aware of any of these being available commercially. For instance:

Engineers Develop Material That Cannot Be Cut - ExtremeTech

I have never tried it, but a layer of asphalt over metal might also be a problem for a sawzall. It isn't that the blade won't go through it, but the asphalt will coat the sides of the blade and it will then probably jam in the groove.