Hex on the Beach

Coconut? Check. Twisty straw? Check. Green, bubbly substance, of unknown origin, with mind-altering effects, delivered upon consumption?... Check?

Whatever this spooky concoction may consist of, how harmful could it possibly be? After all, they're serving it in the Talmuth tavern, and they have always been known for their extensively large menus, and mouthwatering refreshments.