That is Anubis trying to get your browser to do proof of work: https://github.com/TecharoHQ/anubis
Plus, I did manage to pass it once at least.
(PoW is fine, just wish it didn't spin it as an anti-AI thing.)
This is exactly what makes this cringy. There is no reason to anthropomorphize your shitty anti-bot scripts. It's just as annoying as when software goes "oopsie woopsie" when there is an error.