It sounds like the way a Northern Pike will strike at times. They swim up behind the lure - inhale it - and just keep on swimming in the same direction the lure was moving. You only feel a little bump if anything at all. I hooked and lost the biggest Pike I ever had on, exactly like that. I had been casting a small Rebel Crawfish plug for Smallmouth Bass and flipped it parralell to some rip-rap at a ferry dock while waiting for the ferry. Had the drag cranked down tight - because I only back reel for Smallies, and when I felt the light bump and then the line actually went slack, I started reeling fast to catch up - and this Monster Pike rolled on the surface right in front of me - dove and before I could loosen the drag the 6 lb. test line broke. I just stood there shaking. I have caught a lot of Northern Pike in my life - between 15 and 20 lbs. and this one was a lot bigger than the 20's I have caught when I lived in Alaska.