https://en.wikipedia.org/wiki/Carcinisation

An obscure phenomenon for much of the time since its discovery, carcinisation has become more widely known since 2019, having been the subject of a popular internet meme.

And

Beginning in 2019, carcinisation has found popularity as an internet meme. This parodies carcinisation, purporting that crabs possess the "ideal body plan" and conceptualizing the evolution of other animal groups, especially vertebrates, of eventually developing crab-like bodies (often being examples of speculative evolution).