Line your baking sheet with parchment paper and set aside. Preheat your oven to 200℉.
Pour the three eggs whites into the bowl of your stand mixer. Sprinkle the cream of tartar on top so it isn't in one big clump. Mix with the whisk attachment until it turns into a thick foam.
Continue to mix while slowly adding the sugar, about a tablespoon every 30 seconds. Beat on high speed until the meringue can hold a very stiff peak.
Add the ½ teaspoon of vanilla and beat some more. It should be very stiff and shiny.
Spread a little (about ½ tsp.) meringue on each corner of the baking sheet and press the parchment paper into those corners. This will help hold the paper down as you pipe the meringue ghosts.
Spoon the meringue into the pastry bag fitted with the large tip. Pipe meringue onto baking sheet in ghostly shapes, about 2 inches apart. Carefully press the mini chocolate chips, mini M&Ms, or sugar pearls into the ghosts to make eyes.
Bake in the preheated oven until meringues barely start to turn pale gold and are firm to touch, about 1½ - 2 hours. Keep the meringues in the oven and turn off the heat. Leave ghosts in the oven for another hour before removing to counter to finish cooling.
Store ghosts in a sealed container for 1-2 weeks.