lure knocker
n.— «Every fisherman should also carry what is called a “lure knocker,” which is a device with a weight on the end and a short length of chain attached to a long rope. The device will hook onto your snagged lure and retrieve it.» —“Jumbo minnows yielding best results on Clear Lake” by Terry Knight Record-Bee (Lakeport, California) Dec. 12, 2008. (source: Double-Tongued Dictionary)