Today I worked out that if you were unfortunate enough to have 106 leeches attach to you and drink their fill of your blood, you would probably die of blood loss. 

I looked it up because a fictional crime show had someone die of “drugged in leech pond”, and, yeah, it’s possible. Highly unlikely, that’s a lot of leeches, but it could happen. So, like, don’t let that many leeches attach to you.