What arrived explained it all: the molcajete bowl in this case, made from volcanic rock, is heated, and food put into it continue to cook when it arrives at the table. The heat retention of rock is quite impressive, remaining screamingly hot for about an hour.
I envision here a new Korean-Mexican hybrid, beyond the Kogi Korean beef tacos. Bibimbap meets molcajete, replacing the traditional dolsot. And perhaps amplifying the flavors with Mexican salsas in place of the gojuchang.