Fiddler crabs use dishonest signalling to bluff about their fighting ability. When a claw is lost, a crab occasionally regrows a weaker claw that nevertheless intimidates crabs with smaller but stronger claws.

Fiddler crab - Alchetron, The Free Social Encyclopedia

Fiddler Crabs Fighting

Fiddler crab - Alchetron, The Free Social Encyclopedia

Fiddler on the Roof? Northern Extension of Fiddler Crabs' Range

Honesty not always the best policy

Fiddler Crab, Creatures of the World Wikia

Lefty was my favorite B-list Sesame Street character : r/videos

The Fiddler crab on Hilton Head Island Photograph by Kim Pate

Fighting with an unreliable weapon: opponent choice and risk

Coalition among male fiddler crabs