Step 1Peel, seed and puree the pear in a blender. Measure out one-fourth cup puree and set aside. (Or use 2 ounces purchased fresh pear puree.)
Step 2Using a muddler or mortar and pestle, muddle the cherimoya with 1 ounce rum. Pour into cocktail shaker.
Step 3Add the remaining rum, the tequila, agave nectar, vermouth, pear puree, lemon juice, lime juice, pineapple juice, bitters, creme de cocoa and ice. Shake vigorously. Strain into a tall Collins or Martini glass over ice. Serve with a straw.