Max

I semi-regularly put the milk in the cupboard and usually realize when I try to put the cereal in the fridge and it doesn’t fit

I think this is only true for some non intuitive definition of “temperature” of the light source. Fireflies aren’t a blackbody radiator, while the sun largely is. You absolutely can use non-equilibrium/non-blackbody light sources to heat something to hotter than the source. For example, lasers can heat something extremely hot while remaining “cool” (unless you’re considering the non equilibrium temperature of their excited atoms/electrons, which isn’t really fair.)