I got an obviously-AI voice agent spam call yesterday. Had a bit of fun getting it to answer trivia questions (when was the treaty of westphalia ratified? answer in a rhyming couplet) as a precondition to handing over the keys to my bank accounts.

Downside is they most likely are using stolen tokens, not paying themselves so it cost them next to nothing.

Perhaps the future of captcha is anti-captcha. What agent can resist responding with a rhyming couplet or inverting a binary tree?