Dark Chocolate and Oat Clusters

This healthy 4-ingredient cookie is perfect for snacking on the go or wrapping in a lunch bag.
Put the peanut butter, milk, and semisweet chocolate chips in a saucepan; cook over low heat until the crumbs are melted (about 3 minutes). Add oatmeal; remove from heat. Using a spoon or melon ball mold, place 8 ball-shaped servings on a baking sheet lined with waxed paper; let stand in the refrigerator for 10 minutes before serving.