hammerhead
 n.— «Erik again let me get away, but not before we both got called hammerheads for plowing up one of the hairpins as we passed a big pack. “Hammerhead back!…. Another hammerhead back!”» —“Re: Death Ride, or ‘Where I Died On My Summer Vacation’” by Bill Knowlin Usenet: rec.bicycles.rides July 22, 1993. (source: Double-Tongued Dictionary)