Preheat the oven to 375 degrees Fahrenheit and line a sheet pan with parchment paper.

Use a mixer to beat the oatmeal cookie mix, softened butter, water, and egg together until combined.  

Fold in the semi-sweet chocolate chips and then use a 2-inch cookie scoop to place batter onto the sheet pan. Leave about 2-inches between the cookies.

Bake in the oven for 10-12 minutes, or until cookies are golden brown around the edges. Set aside to cool off when they are done baking.

Prepare the frosting by putting it in a bowl and adding red food coloring to the frosting. Add enough food coloring so that the frosting resembles a blood color.

Use a knife to cut each cookie in half. Spread a thin layer of frosting on the flat side of both cookie halves. Set aside half of the cookie halves.

On the other cookie halves, place a line of mini marshmallows around the curved edge of the cookie half, in the frosting. The frosting should hold them up, and the marshmallows should be touching and resemble teeth. Stand 2 or 3 more marshmallows on the straight edge of the cookie as extra support, optional.

Once done with the marshmallows, grab the remaining cookie halves that were set aside and place them on the top of the marshmallows on the other cookie halves. The frosted side will be face down, resting on the top of the marshmallows. The curved and straight edges should match up with each other. It should resemble a mouth with teeth once assembled.

Add two almond slivers in between the marshmallows, as bookends to the front 3-4 “teeth.” These create the fangs.

Plate and serve.