I was fishing today, using a beetle spin, and bam felt a strike, set the hook, feel weight, and broke off immediately. I have my drag set light enough that I will strip some line with a 3 pounder pulling, so reasonably light, and using 12 pound Big Game.

 

When I pulled my line in and looked at the end it was curly for about 1/2"; the same way as if you use a pair of scissors to curl a ribbon. Line is fresh and I had checked it several times for line wear.

 

I first thought, man I hate to break off in a fish, then I got to thinking, I wonder if it was a huge snapper and he bit my line, curling it in the beak as it broke free?

 

 

That sounds like your knot slipped, leaving the curly. Snapping turtle bites feel like someone hitting your hook with a rock.

I considered my knot had slipped, but I was using a trilene knot, and I've perfected it. I have a certain way of tying it and it's never failed. I wonder if the double wire eyelet of a beetle spin may have caused an issue with it? While I don't use a beetle spin a lot,  I've caught several fish with beetle spins tied with this knot previously.

Usually that little "curly tail" is a sign of a knot that slipped. 

 

It's quite possible your line slipped between the double line tie & broke, this to will leave that curly tail. Bettle Spins are notorious for this.

 

A turtle bite is usually a clean cut.