Charon’s obol (aka danake) is the coin placed in or on the mouth of a dead person before burial. Greek and Latin literary sources explain it as a payment or a bribe for Charon, the ferryman who conveyed souls across the River Styx, which divided the world of the living from the world of the dead.
More precious gold or silver coins were seldom buried with the deceased so a type of “ghost money” was made instead by making an impression of a real coin into thin gold foil. These types of pseudo-coins were too flimsy to use as currency. This particular gold piece (c. 5th-1st century BC) was obviously modeled from the bee drachms from Ephesos (or Arados). Actual coins were also buried with the dead as well, though they were generally small denominations.
Two more examples of Charon’s Obols can be seen here and here.