Preheat oven to 275° and place oven racks in the two lowest positions.
Prepare two large baking (cookie sheets) sheets with parchment paper.
Drain and reserve the liquid from a can of chickpeas. Measure out one cup LESS one tablespoon.
Put the cream of tartar in the bowl of your stand mixer.Pour the strained aquafaba on top of the cream of tartar.
Using the whisk attachment, turn the mixer on low and mix the cream of tartar with the aquafaba.
Slowly increase the speed to medium. Beat until the mixture is foamy.
Gradually increase the speed to high and beat for a few minutes or until soft peaks form.
Continue whisking on high while adding in the sugar, Tablespoon by Tablespoon, beating well between each addition of sugar until stiff glossy peaks form.
Add the vanilla and beat for one minute.
Sprinkle the cornstarch on top and continue beating for one more minute.
Cut the tip from a (disposable) pastry bag and insert a large (1 inch) round tip. If you don't have a large tip, just use your pastry bag.
Carefully spoon in whipped meringue, filling the bag no more than 2/3 full. You will refill as necessary.
Pipe out the ghost/cone shapes directly onto your prepared baking sheets. Start with a larger round base. Pull up while decreasing the pressure until you have a cone.
Bake on the lower oven racks for 75 minutes, rotating half-way through.
Once the baking time is up, turn off the oven and prop the door open a couple of inches until the oven is cooled. This might take up to an hour or more.
Remove the meringues to a wire rack so the bottoms can dry. Continue cooling till completly cool and dry.
Decorate the ghostly faces with black frosting gel.