Discredited Meme: The "Garfield [something that sounds like minus] Garfield" bit after one use too many. It was officially axed when they made a strip with the Terminator going back to stop the meme's creation.
This strip became this when the real strip really did have a strip◊ about Garfield chasing a laser pointer two months later.
Similarly, this strip features Garfield paying Odie like a hitman to knock the head off a snowman, which became much less absurd when the actual canon◊ featured Garfield doing the same to an unnamed dog to sic Nermal.
The annotation of #88, a recreation of a mezzacotta comic, states "The next trick will be turning Garfield and Jon into Lightning Made Of Owls characters." They don't turn into them, but this comic was made a year later, and then this extremley meta one a few years after that.
In this strip, the author points out that, despite his expectations, editing the strip where a mouse declares Jon's house part of "the Empire of Mice" to have the mouse representing various other fictional empires looked like it would never become a meme. The very next day, this was posted. And both author's notes end with a slogan praising the ruler of the empire featured in the strip. (In case you're wondering, the second strip couldn't have been made in response to the first due to the lead time caused by the Strip Buffer).
Even better, this contribution was posted a few weeks later, which had been submitted before either of the above.
Strip 2564 has Jon delivering an epic comeback line (even though the author, for some reason, claims that it "makes no sense") to a lover who rejects him, in contrast to the original strip where Jon thinks of the comeback after it's too late.