In a cocktail shaker add Aperol, spiced rum, pineapple, lime, and simple syrup.
Add ice and shake well.
Strain over fresh ice in a short glass.
Garnish with a lime slice and serve.
Notes
If you don't have Aperol you can use Triple Sec or Cointreau (other orange-flavored liqueurs) plus a few drops of bitters. Taste it and adjust flavors before serving by using a cocktail straw. Here's how: Insert a cocktail straw into the liquid, and then put your finger over the top of it to cause suction. Just make sure to put the drink side into your mouth before taking your finger off!