Three Little Piggies - S2.E23

The pigs build structures much like the three little pigs: one made of straw, one made of wood (instead of sticks), and one made of bricks. When they hear the howling, they think it's the big bad wolf. So, they run and hide in the straw house, but it collapses. Then, they hide in the wood house, but it collapses, too. They hide in the brick house when the howler arrives and it turns out to be another pig. But the pig has a cold and his sneeze topples over the bricks.