One is an ever so scary phantom to keep the kids, or entire populace in line. Witches, devils, demons, In the USA, communism, communists, socialism and socialists were also used as bogeymen.

The other is a confuselating and bewildering variant: Per da wiki,

the interjection "fnord" is given hypnotic power over the unenlightened. Under the Illuminati program, children in grade school are taught to be unable to consciously see the word "fnord". For the rest of their lives, every appearance of the word subconsciously generates a feeling of unease and confusion, preventing rational consideration of the text it appears in. The uneasiness and confusion create a perpetual low-level state of fear in the populace. The government acts on the premise that a fearful populace keeps them in power.

Here in the USA, socialism and socialists have been and still are being used as Fnords, but the principal fnord today is PUTIN who is also, in regular font, also a bogeyman of sorts.

PUTIN! imperialism is horrible and is destroying the world and causing misery, want, poverty and broken infrastructure at home to funneling all wealth and productivity into the military, endless wars and the pockets of parasitic oligarchs who profit, directly or indirectly from our endless wars. PUTIN!

Be vary afraid, but, be not afraid, rest comfortably in the arms of Uncle Sam the strong savior and ignore all the PUTIN! racism, hatred, discrimination, poverty, orchestrated class warfare against the hoi polloi and then endless evil wars and warfare PUTIN!

That's right kiddies, eat your plastic sugary food and sign up to join our glorious armed forces which will care for you now and forever. If you don't, Putin will get you. Putin, the evil horrible one responsible for all the ills of the world, like PUTIN all those horrible and unnecessary deaths in Yemen PUTIN

sleep now, sleep and dream of global hegemony and fancy cars and houses and maids and gardeners and forget PUTIN the endless killing PUTIN.