Line a 8 or 9-inch square pan with parchment paper, leaving an overhang. Butter the parchment.

In a microwave-safe bowl, combine the butter, cocoa, sugar and evaporated milk. Microwave on high until mixture boils, about 2 minutes. Remove from microwave and whisk until smooth.

Mix in powdered sugar and vanilla. Use your hands to fully blend in powdered sugar, if needed. Spread evenly in the prepared pan.

In another microwave-safe bowl, heat the caramels and water on high for 1 minute, 15 seconds, or until melted. Stir in peanuts. Spread peanut and caramel mixture over fudge layer in pan.

Microwave chocolate chips and vegetable oil at 50% power for one minute; stir. Continue to microwave at 15 seconds intervals until completely melted and smooth. Spread melted chocolate over caramel layer.

Chill until firm. Bring to room temperature before serving.