Preheat oven to 350 degrees. Line a 12-cup muffin pan with liners.
Make the crust: Mix crushed cookies and melted butter in a small bowl. Divide evenly amongst muffin liners and press to compact.
Make the cheesecake: Beat the cream cheese until fluffy. Add in the sweetened condensed milk, pumpkin, and pie spice.
Stir until combined. Evenly divide among crusts, filling liners almost to the top (they will not rise). I had some left over.
Since it is egg-free, it would make a great dip! (Or, you can make more crusts.)
Bake for 18-20 minutes until the cheesecake shows slight cracks on the top. Cool completely before making frosting. (I chilled mine overnight in the fridge to make sure they were completely cooled.)
Make the meringue icing: Bring a few inches of water to a gentle simmer in a saucepan large enough to hold a standing mixer bowl above the water. Whisk the egg whites, sugar, cream of tartar, and salt together in the bowl until combined.
Set the bowl over the simmering water and whisk constantly until sugar is completely dissolved and mixture is smooth, about 2 to 3 minutes. Place the bowl on the standing mixer fitted with the whisk attachment and beat at medium-high speed until meringue holds a soft peak, 4 to 5 minutes. With the speed on low, add the vanilla extract; increase speed to medium and continue whisking until mixture is glossy and holds a stiff peak, 1 to 2 minutes more.
Place meringue in a large ziploc bag with the tip of one corner snipped off. Pipe the meringue onto the cheesecakes by placing the tip of the bag over the center of the cake, and piping one large circle. Continue piping, raising the bag straight up, until you have the height ghost you want. Release pressure on the bag and pull it away quickly to create the top of the ghost. Add eyes using a toothpick and black food coloring. Store in refrigerator.