<human>: How do I make a pom-pom for my Halloween costume?
<bot>: To make a pom-pom for your Halloween costume, you will need a few materials. You'll need yarn in the color of your choice, scissors or an appropriate pair of fabric shears, and a needle and thread. First, cut a length of yarn about twice as long as the desired size of your pom-pom. Then, fold the yarn in half and hold it tightly together with one hand while you insert the needle through the center of the folded end. Pull the two ends apart until they are even. Finally, tie a knot at the end to secure the pom-pom.