To get the third easter egg and 1000 coins do the following. Go to the "nice to siege you" level on story mode. Go to where the proffesor is and go down the cliff. You should see an entrance. Go inside to find a worm dressed like a rabbit. A message will appear saying "you found an easter egg". Now finish the level (it doesn't matter if you win or lose). You now have the third easter egg and 1000 coins.