If I cut up a nightcrawler (for bait), can it (they) regenerate?
Maybe that would make me feel better. 
Peace,
mangeorge
Certainly not, after the pieces get eaten by a fish.
Only the head end can regenerate, and then only if there’s enough of the original worm. The rear end dies.
I’ve used a lot of nightcrawlers in my life. They seem to die very easily. But I have to admit I’ve never waited long enough to see if they regenerate. The half-crawlers have to be tossed out if they’re not used.
I’m working out my new ultralight combo with a 1/32 oz float and jighead with about 3/4" of worm. Guess the rest can go to the crows. Crows love me. 
The common ground worm we dissected in my 7th grade science class could regenerate its rear portion so long as its forward 21 sections were intact. All the organs are up there; the rest, no matter how long the worm got, was just colon (or the analogous structure). So if it’s convenient, you can make sure you leave lots of room at the front and just chop off and use the back part.
–Cliffy
The crows aren’t going to like you one bit! 
I’m no expert, but I thought it was Wolverine that regenerated, not Nightcrawler.