Line an 8-inch square pan with waxed paper or spray with cooking spray.
Place 1 almond bark half in a microwave-safe bowl; heat in the microwave, in 30-second intervals, stirring after each melting until smooth, 1 to 3 minutes. Add peanut butter to melted almond bark and mix well. Add the remaining almond bark to the bowl and push to the bottom of the bowl.
Heat mixture in the microwave for 1 minute; stir to break up any large pieces. Continue heating in microwave, in 30 second intervals, until completely melted. Pour fudge mixture into the prepared square pan.
Melt chocolate bars in a microwave-safe bowl in 30-second intervals, stirring after each melting, for 1 to 3 minutes. Drizzle melted chocolate over fudge. Swirl the chocolate into the fudge using a knife.