As a zoomer, I'll use my power to explain some things.
Big Chungus is a meme from late 2018, depicting an out-of-context frame from a Looney Tunes cartoon with a fat Bugs Bunny (
this frame specifically). The meme peaked when
this photoshopped image was created, which also prompted
this guy to make a video were he made a copy of the fake game to sell to Gamestop. As you might expect, there wasn't a lot of other ways you could make it funny, & people quickly got sick of the meme. Over time though, it made a bit of a resurgence, not because people changed their minds about it not being that funny, but because it entered "so bad it's good" territory, where the butt of the joke was the cringe-worthiness of the person making it.
About a year later, a similar effect happened with the popularity of the video game Among Us & the cringe-worthiness of the people making references to it. For those who don't know, Among Us is a party game where one player is assigned the role of "the imposter" & has to sabotage the tasks of the other players without getting caught. The social dynamic of the game led YouTubers to milk lots of content out of playing it with their friends, & thus the game exploded in popularity. Anyway, references to it (like calling people "sus" [suspicious], talking about finding the imposter & completing tasks, etc.) quickly became memes & equally quickly became disliked memes as people found them annoying. At this point a similar thing happened with Big Chungus, where people posted
memes referencing the game in as cringe-worthy of a way as they possibly could, & then the appeal of the memes became to laugh at the people making them rather than the references themselves.
Fast forward to today, & someone (possibly Kmac: a music YouTuber that also dabbles in memes sometimes) sent a paid request for James LaBrie to reference both of these things at the same time, & now people are finding it funny out of both ironic enjoyment & laughing at the absurdity of the whole situation.
Hope that helps.