A Marlinespike (or Marlinspike) is a pointed general-purpose tool for knotwork which principally assists the user in creating splices in rope and untying knots - although as a tool frequently to hand in sailing and knotting contexts, it has been used for myriad other applications.
A marlinespike can be used in combination with a Marlinspike Hitch as a tool for improving the user’s grip on a rope or cord, to effect a stronger pull - in which case its pointed shape is less important and it is simply being used as a strong ‘handle’ - any suitable strong bar would also work.
A stainless steel Marlinespike with a ‘shackle eye’ for additional leverage when opening a shackle.