Line a tray or plate with parchment paper. This keeps the cookies from sticking while the chocolate or icing sets and makes transferring them easier.

Melt the chocolate chips or wafers in a microwave-safe bowl in 15- to 20-second intervals, stirring after each interval. Stop as soon as the chocolate is smooth; if using black decorating icing, use it directly without melting.

Carefully separate each sandwich cookie slightly, or gently loosen the cream filling with a knife. Avoid forcing the cookie apart, especially if the filling is firm, because the chocolate biscuits can crack.

Insert eight short pretzel pieces into the cream filling, placing four on each side of the cookie. Press the cookie back together gently so the filling holds the legs in place.

Dab a small amount of melted chocolate or icing onto the front of each cookie and attach two candy eyes. Use only enough adhesive to hold the eyes so the cookies stay neat.

For a raised spider body, attach one small chocolate candy or mini peanut-butter cup to the top of each cookie with a little melted chocolate. This optional addition creates a more dimensional spider shape.

Let the cookies stand until the chocolate sets, or refrigerate them for 10 to 15 minutes to speed up the process. Serve once the pretzel legs and candy eyes feel secure.