Place eggs in a saucepan and cover with water. Bring to a boil, remove from heat, and let eggs stand in the hot water for 15 minutes. Remove from hot water and chill at least 30 minutes in a bowl of cold water or in the refrigerator, until eggs are cold.
Prepare egg dye according to package directions in a large metal or glass bowl.
Gently crack eggs but do not remove shells so that the egg dye can reach the egg whites.
Place the cracked hard-cooked eggs into the dye, working in batches if necessary, until dye seeps through the cracks and colors the eggs slightly, about 5 minutes per batch.
Rinse eggs and peel to expose the green marbled color; slice eggs in half lengthwise.
Scoop egg yolks into a bowl and mash with a fork and mix in the mayonnaise and celery; stir green food coloring into the yolk mixture.
Spoon the yolk mixture into the egg halves; top each egg half with a parsley leaf.