I always have to add a batch of grumpy monster rocks!! **SUPPLIES** If you need rock painting supplies please consider using our links below. We will make a small commission at no extra cost to you. I used my pastel Posca colors for all my Halloween rocks last year... you can fill in your monsters with any colors pens/acyrlics you want. I did use an extra fine tip black and white (1M) Posca or Artistro both have excellent extra fine tip pens. I used one of each in this tutorial... Shop supplies