A fun real-life application for cross-linking and polymer chemistry, this activity demonstrates how a simple material extracted from seaweed is used as a common thickening agent for popular candies. Sodium alginate is long-chain, natural polysaccharide polymer that contains sodium ions. When placed in a solution of calcium chloride, the divalent calcium ions displace the sodium ions and the polymers are quickly cross-linked to form a worm-shaped gel. These gelatinous worms can be safely examined since the polymer is a nontoxic food additive. The demonstration includes enough materials to for 10 repetitions. The Activity contains enough materials for 12 student groups to prepare several worms.