Preheat oven to 350 degrees. Pour the creamed corn into a bowl. Crack the egg into the empty can, fill can halfway with milk, and whip up with a fork. Add to bowl. Add sugar and mix. Crumble saltines with hands and mix into ingredients in bowl until resembles thick batter (about 3/4 strip). Pour into greased casserole and pat some margarine (or butter) on top. Top with more crumbled saltines and let sit for at least 15 minutes. Then bake for an hour +/- 15 minutes (depending on oven and casserole shape - I use a deep bowl and bake the doubled recipe for 1 h 15 min).