I urge everyone to bookmark that blog; it is always a fascinating tour of the weirder and wonderfuller places on our planet. And let me leave you with this simply jaw-dropping video of undulatus asperatus in action.
(A sunscreen with a physical block like titanium dioxide or zinc oxide can be applied last, after a serum or moisturizer.) Apply a serum next and, finally, moisturizer if you need it. Polis also recommends serums or sunscreens with moisturizers built in because they save time.
Then, before the moisturizer stage, comes a litany of products that can be downright confusing to differentiate. The stage following cleansing is called the treatment stage, which in Korea can include serums, essences, boosters, concentrates, and ampoules.