A Catalytic Converter naturally gets hot due to the exhaust temperatures and fuel being burnt by the engine.
But a catalytic converter really shouldn't get to the point of being red hot and if your catalytic converter is becoming red hot then it means your engine is likely misfiring either on one cylinder or on more than one cylinder and you should have the engines electrical system checked out.
A catalytic converter glowing red hot usually means that fuel is not being burned properly by the engine or that raw fuel is getting into the catalytic converter.
Another less common cause of a catalytic converter glowing red hot is a clogged catalytic converter but most times it's something else causing the engine to misfire.