Here’s one of the more surreal corners of industrial medicine: crab blood donors. Apparently the best way of detecting some bacterial contamination is to add some crab blood extract to it, and see if it clots. So 250,00 crabs a year are scooped up and part-drained of blood, before being released with just enough blood left that most of them will survive the process.
To make it even odder: crab blood is blue.
[Thanks to Julien for pointing me at this bizarre micro-industry]