I was trying Kenji's roasted lobster technique for lobster rolls last night (though I was harvesting meat for risotto), and let's just say "the tail may wiggle a little" is a gross understatement. For a solid 10 minutes after slicing Mr. Lobster's head in half, the tail would recoil violently at the slightest touch of the shell.
Anyway, I was a little slow-mo about putting the knife through the lobster's head and the little dude really kicked around a bunch before I plunged the blade in. I've done this a few times and I have never seen the amount of (jet) black gunk as I saw last night. The tail meat was actually discolored from the stuff.
I've heard that some animals release toxins when they know they're about to die. Is this true for lobsters? Should this be a consideration?