In a mixing bowl, combine sugar, margarine and crushed pineapple. Stir in a small amount of pineapple juice if the mixture needs more moisture. When the mixture is well blended shape it into two 1/2 pound eggs (or a bunch of smaller eggs). Freeze for one hour.
While the eggs are freezing, cut semi-sweet chocolate into small pieces and place in top of double boiler with shortening. Melt over medium heat, stirring frequently until smooth. Stick a long-tined fork in top of each pineapple egg, dip it in melted chocolate to cover then drain on waxed paper.