Line a baking tray with baking paper.
In a large pot, melt the butter on medium heat, then add the mini marshmallows and stir to melt.
Once melted, add in the crisped or puffed rice cereal, and stir to combine.
Place the mixture in the lined baking tray and pat down to even out and press firmly together. It should be about 3cm thick. Set in the fridge to cool for about 3 minutes.
Cut the rice crispy treats into rectangles of about 3cm x 4cm.
In a double boiler, melt the white chocolate, and place in a piping bag.
Place the edible eyes on the top half of the rectangles, then stick the eyes on with a small amount of chocolate.
Pipe the chocolate in lines across the rectangle.