The usage of Lovecraftian (q.v. H P Lovecraft) references during internet discussion or debate.
It does not indicate loss during internet debate, as does Godwin's Law (q.v.) but it does indicate that the discussion has moved to the point where it is ripe for ongoing mockery
The thread was subtly won with the Arkam Effect when his comment carried overtones of eeriness and alien logic.
The Arkham Effect was in blatant use when she wrote "bugger me, you're Great Cthulhu's grumpy, uglier brother, aren't you?"
The Arkham Effect can include a form of double entendre like "I can tell the from your reasoning that you're a deep one".
When a fandom of a game, show or other form of media is left without content for a substantial amount of time the fanbase will start going through a period of insanity where they make memes and jokes that would not make any sense to a mentally sane person
Wow none of these memes make any sense they aren't even talking about the show
that's the arkham effect for you
When a subreddit randomly goes batshit insane, with stupid shitposts and genuinely insane people. Originally from r/batmarkham, hence the name.
Guy 1: All of my favorite subreddits are being flooded with stupid shitposts. What the fuck does "is he stupid?" even mean!?
Guy 2: Blame the Arkham Subreddit Effect...
Guy 1: Why?
Guy 2: Just take a stroll through r/batmanarkham and come back after 10 seconds.