A startup founder asked me to write a fake negative review about my current employer as a culture fit test

I have been stuck in a highly toxic corporate role for two years and recently started interviewing with a rapidly growing tech startup in my city. The interview process has been intense but extremely promising. I met with the CEO for my fourth and final interview yesterday morning. We instantly clicked and he told me I was the perfect candidate for their marketing lead position.

Toward the end of our conversation he leaned back and asked how comitted I really was to leaving my current firm. His startup is a direct competitor to my current employer. I assured him I was fully ready for a transition. He then told me they have a very unconvnetional way of testing loyalty. He asked me to go on a popular employer review website and leave a harsh anonymous review trashing my current company.

He specifically wanted me to mention rumors about their product pipeline failing and send him a screenshot before they draft my offer letter. He laughed it off as a fun little initiation ritual to prove I am a real shark who is ready to disrupt the market.

I was completely caught off guard. I desperately need to escape my current work place because they are silently planning mass layoffs for early February 2025. This startup offer comes with a massive pay bump and great benefits. However asking a candidate to purposefully sabotage another business publicly feels incredibly unethical.

I tried to laugh it off in the room but he sent me an email this morning asking if I had completed the small task yet. I am sitting here staring at the screen. If I refuse on moral grounds I am almost certain he will pull the offer. Is this type of aggressive tactic becoming normal in the startup world right now or am I stepping into an even worse work environment? I honestly do not know how to reply to his email without ruining my chances.