Put frozen bananas, Greek yogurt, and strawberry ice cream in a blender and blend until smooth.
Add vodka and marshmallow fluff and blend until well-combined.
In the bowl of a stand mixer or in a large bowl with a hand mixer, beat heavy cream and sugar until stiff peaks form. Stir in vanilla extract.
Pour milkshake into two glasses and stir in a little bit of chocolate syrup into each. Top each milkshake with whipped cream, crushed peanuts, and some sprinkles.