In a medium mixing bowl, combine Rice Krispies, peanut butter, softened butter, and powdered sugar. The mixture will be thick so you may need to mix with your hands.
Line a baking pan with parchment paper or a silicone baking mat, then roll the mixture into balls roughly 1 inch in size, placing them on your prepared pan as you go. Transfer to the freezer to chill for 30 minutes.
In a microwave safe bowl, combine chocolate chips and 1 cup butterscotch chips then microwave in 30 second intervals, stirring in between, until melted and smooth.
Working one by one, coat each truffle in the melted chocolate, let any excess chocolate drip off, then return to the baking sheet.
Melt the remaining butterscotch chips and vegetable oil, then transfer to a ziploc bag, cut off one end, and drizzle the butterscotch chocolate over the truffles.
Pop in the fridge or freezer for 30 minutes to set the chocolate drizzle. Once set, carefully break off the excess candy-coating pieces around each truffle before enjoying!