Lytocrioceras
Lytocrioceras is a genus of ancyloceratine ammonites from the Lower Cretaceous with a shell that resembles a safety pin. The shell begins as a loosely wound spiral, followed by a straight shaft which makes a U-turn to go back is somewhat the opposite direction, ending in a jog, offset from the original coil. "Lytocrioceras" was originally included in the Ancyloceratidae (Lytoceratina), united with other similar forms but has since been reassigned to the Macroscaphitidae.