Fill a cocktail shaker with ice, and pour in the green apple liqueur, sour apple schnapps, lime juice, and simple syrup.
Secure the lid tightly and shake vigorously for about 15 seconds until the mixture is well chilled and frothy.
Strain the mixture into a chilled martini glass, ensuring a smooth, vibrant green liquid flows into the glass.
Optional: garnish with a spooky themed element, such as a green gummy worm or a small plastic spider, to enhance the Halloween vibe.
The Poison Apple Martini is ready to serve, showcasing its bright green hue and inviting chill, perfect for haunting your Halloween party.