Prepare the chocolate fountain according to the manufacturer's instructions.
In a double boiler or microwave-safe bowl, combine the semi-sweet chocolate chips and heavy cream. Heat gently until melted, stirring to combine.
Stir in the vegetable oil to create a smooth consistency. If using the microwave, heat in 30-second intervals, stirring after each, until fully melted.
Pour the melted chocolate mixture into the fountain reservoir, turning the fountain on to allow the chocolate to flow.
Arrange the dippable treats (strawberries, marshmallows, pretzel rods, pineapple chunks, and pound cake) on a large platter.
Provide skewers or fondue forks for guests to dip their chosen treats into the flowing chocolate.
Make sure the chocolate is not too thick; if it is, you can add a little more cream to adjust the consistency.
Feel free to vary the dippable items according to your guests’ preferences. Other options could include graham crackers, cookies, or bananas.
For added flavor, you can infuse the chocolate with a splash of vanilla or liqueur.