Isn't it Young? Totally MZ!

Origin

The line comes from Avatar Singer, a metaverse music survival show MBN aired from August 26 to December 16, 2022. Billed as Korea's first metaverse variety format, it had real singers performing from behind avatars while a panel judged them. The meme's starting point is a moment when panelist Lip J reacted on air with "That's so totally MZ, isn't it?" Program details are documented in the Namu Wiki entry on Avatar Singer.

What made the remark stick was the reception of the show itself. It led with cutting-edge technology, but many viewers found the actual avatar work underwhelming — and having the panel talk up how trendy it was using the word "MZ" in that context read as forced. Lip J later said on the web show Psick Show that she had not even known she had said it; the dominant reading is that she was reading a line the production staff had prepared.

Spread

It began circulating as a meme around September 2022. The key point is that its usage hardened into the opposite of its literal meaning. It is not used to praise something genuinely young and stylish, but to mock — talking up something dated, ordinary, or frankly tacky as though it were the height of trendiness.

A fixed form emerged as well: when someone posts something unremarkable, the comments line up "That's young, isn't it?" and "That's so totally MZ." It most often serves as a tool for pointing out marketing or programming aimed at young people that misses its mark.

Usage

Sarcastically hyping something dated or ordinary as though it were trendy.
Calling out forced "MZ" marketing or programming.
Attaching it to your own tastes, self-deprecatingly, knowing they are unfashionable.
Posting the two sentences in sequence in a comment thread as a stock bit.