Add ice to a cocktail shaker. Then add vodka, Kahlua, and coffee concentrate to the shaker.

Shake vigorously for about 30 seconds until combined and chilled. Strain the mixture into a martini glasses.

Add some marshmallows to a microwave safe bowl and melt for 20-30 seconds or until melted.

Using a spoon scoop the melted marshmallows and string it over back and forth of the edges to create a cob web effect.

Add 3 coffee beans to the cocktail and a plastic spider ring on the rim for garnish if you'd like.