In a medium saucepan, melt the butter over low heat.
Add the mini marshmallows and stir continuously until fully melted and smooth.
Remove from heat and stir in the Rice Krispies cereal until evenly coated.
Press the mixture into a greased or parchment-lined 9x13-inch pan using a rubber spatula.
Let the treats cool for 10–15 minutes, then cut into 12 rectangular bars.
In a microwave-safe bowl, melt the white chocolate chips in 20-second intervals, stirring between each until smooth.
Transfer the melted chocolate into a piping bag or zip-top bag with the tip snipped off.
Drizzle the white chocolate over each bar in zig-zag patterns to resemble mummy bandages.
While the chocolate is still soft, press two candy eyes onto each bar.
Allow the chocolate to set completely before serving.