Semi-related but I needed a CAPTCHA on my site[0] mainly to block comment form spam and settled on repurposing a fun method I’d seen before. Is definitely not foolproof (or hard at all), but I really liked making it.
Some of which have been observed to be associated with certain countries.
There are bad actors. There are bad groups of actors. There are bad political regimes of groups of bad actors. There are countries made up of bad political regimes made up of groups of bad actors.
Haven't looked at the devconsole but it'd probably be easily bypassed by someone dedicated.
If you want to stop a dedicated attacker ready to spend time to attack your site, it won't work, but nothing will. If you want to stop a generic bot going over the internet and submitting all forms it finds with spam, this will work, and might even work better than wide-spread solution for which the bot has a countermeasure.
It has the advantage of being novel for the user rather than doing the same Google/Cloudflare/... CAPTCHA for the 10th time that day.