This makes an interesting glob of "scar" tissue to use for costuming for Halloween, plays, etc.

 

1 package unflavored gelatine
2 tablespoons hot water
Red food coloring (if needed)
A little baby powder

 

Mix gelatin and hot water in a small bowl and stir till the gelatin thickens. Add the food color to a small amount of the scar goop, if you want the scar to be 'fresh'. Use a wooden craft stick or your fingertip to apply the "scar" to your skin. Dust with a small amount of baby powder until it resembles skin.