There’s a punctuation style that seems to have appeared relatively recently where the writer puts a period (full stop) after each word in a sentence or phrase to indicate that each word is to be emphasized individually, with a short pause after each word. Often the words are also capitalized. Like
That was the Best. Concert. Ever.
Must. Stop. Eating. Now.
I am Really. Tired. Of. This. Affectation.
I think it’s trying to reproduce a verbal rhetorical style that I associate with Comic Book Guy on The Simpsons. My impression is the written form is fairly new; within the last 10 years or less. Is that accurate? Is it possible to identify a specific source of this style?
It might be from the Comic Book Guy, but it’s definitely older than 10 years; I found a 13 year old StackExchange thread asking about it. Which also speculated it was from the Comic Book Guy, but no one was sure.