From what I know, temperature is defined to be the average kinetic energy of molecules within a system while heat is said to be the total kinetic energy of molecules. I know this might be something we can never achieve in real life but here's how my thought process went. Imagine you have a box with radiation shielding such that there is no radiation process involved. If you can somehow suck out all the molecules leaving just one molecule behind, depending on how slow or fast this molecule travels you can have very little "total kinetic energy" with quite high temperature(average kinetic energy). I guess when the molecule bounces off the wall there could be a sudden change in temperature. I am aware that temperature is only defined when you have a reasonable amount of molecules but if we can somehow come up with the setting I mentioned, then what happens in real life? do we feel hot? cold?