Cut the black card into a cape shape: a rectangle slightly wider than the bag, with two curved shoulders at the top and a slightly scalloped hem at the bottom. An adult should cut this. The cape should be about 18 cm tall so it wraps around the bag from behind.

Cut a red card collar: a curved band about 3 cm wide and the same width as the cape top. This is the red lining visible above the cape neckline. Glue it along the top edge of the black cape on the front side, curling it slightly so it stands up like a collar when the cape is on the bag.

Apply glue to the back of the cape and press it to the back of the bag, wrapping the top corners to the front so the collar peeks above the bag opening. Hold for thirty seconds. The bag should now look like it is wearing a cape.

Cut two small fang shapes from white card: narrow triangles about 2 cm long. Glue them below the bag opening at the front, pointing downward and slightly apart. Let dry.

Draw or paint two red dot eyes on the upper front of the bag, above where the fangs sit. Add two small dot pupils in black marker on each red dot. The face is deliberately minimal.

Fill the bag with sweets before closing. The fangs sit at the front opening so the bag looks like it is biting anyone who reaches for a treat.