Probably the earliest somewhat official mention of the term occurred on April 4th, 2010, on Urban Dictionary, when its user tankedgirl submitted an entry for "beetlejuiced," defining it as a phenomenon that occurs when a person appears after they have been mentioned several times in conversation.

The earliest known use of "beetlejuicing" in reference to a thread was posted in the r/AskReddit subreddit on January 13th, 2013. There, Redditor bigfrank84 replied to a comment containing the name "Big Frank," to which another Redditor, tynosaur, responded "One of the best instances of Beetlejuicing I've ever seen."

The word itself is derived from the 1988 American horror comedy film Beetlejuice.

It has a scene where the titular ghost explains to the protagonist Lydia Deetz that she can summon him anytime by repeating his name three times.

"I can't help you from this side, but here's how we do it. So simple. Say my name three times," the ghost says. "That's all. I'll be all yours. Then I'll bring you over here in style."

The subreddit 'Beetlejuicing' was created on the same day tynosaur made the aforementioned comment.

In the nearly decade that has passed since then, it has grown into a community of 469K members and that number puts it among the top 1% of subreddits.

But self-reference is spread far beyond internet comments. For instance, a picture could be considered self-referential if it contains a copy of itself and a piece of literature could be considered self-referential if it includes a reference to the work itself.

In philosophy, self-reference is primarily studied in the context of language and is to a large extent centered around paradoxes.

A paradox is a seemingly sound piece of reasoning based on apparently true assumptions that leads to a contradiction. One of the most popular examples is the liar sentence: "This sentence is not true."

Self-reference within language is not only a subject of philosophy but also a field of individual interest in mathematics and computer science, in particular in relation to the foundations of these sciences.

However, is there anything that makes a concept come to life more vividly than silly internet jokes?