Fulling Mill Croston's Bung Buzzer Wildcard - Barbless (Yellow)

The one that does not make sense

Every set of four needs one that does not make sense, and yellow is it. There is no natural it is copying and no clever reasoning behind it. What there is, is the well-documented habit trout have of taking something that looks like nothing at all after refusing three careful imitations in a row. Fish it when the sensible colours have had their turn and the session needs changing rather than continuing.