It happens more than you think, and it is usually a Bass, but sometimes its a Pickerel and more often than not its a big one. I was once lucky enough to watch a 3lb Pickerel nail my 9" sledge in 8 feet of water, what a site that was.

Jack caught this 7 3/4 lb Pickerel while trolling for Muskie with a Believer. Dan caught this 5 lb'er while casting a spinner bait
   
Heath with a 5 1/2 lb Smallmouth - Casting a Bucktail Mark caught this 6lb 81/2 oz smallmouth, casting a black spinner bait.