Check out doing a compression bomb too, you can host a very small file for you that uncompresses into a massive file for crawlers and hopefully runs them out of ram and they die. Someone posted about it recently on HN even but I can't immediately find the link

It's either this one https://news.ycombinator.com/item?id=44670319 or the comments from this one https://news.ycombinator.com/item?id=44651536

I also recall reading it. I think wasting their time is more effective than making them crash and give up in this instance though.