Noooooooooo really? And here I thought she was just slightly off-panel for the last couple Acts.
In the event you're serious and don't actually know about that godawful meme, it started way back when Nepeta died a tragic undeserved death via clowning. It was pretty much made in response to an influx of fans theorizing/hoping she might still be alive. The joke (which is literally just shouting "Nepeta is dead" when people talk about her), in short, is "your favorite character is dead and no longer relevant, so there's no need to ever talk about her ever again." It still tends to be brought up any time people bring Nepeta up ever, despite being long, LONG, after the original stimuli had faded into obscurity.
Now that's Nepeta's alive again I can blissfully chop off this hateful thing's head, nail its coffin shut, and burn its whole mausoleum down and never have to hear from it ever again.