Using a serrated knife, gently cut one of the graham crackers into 4 quarters.
Place the other 2 graham crackers in a zip top bag, then crush roughly with a rolling pin (not too fine, you want some small chunks.) Transfer to a small bowl.
Dip the rim of a mason jar in the chocolate. Let excess drip off.
Gently roll rim in crushed graham crackers, rotating to coat outside of glass.
Using a small spoon, pour a little chocolate on the inside of the rim and allow to drip down.
Repeat process with other mason jar. Refrigerate both jars until chocolate is just set, about 5 to 10 minutes.
Dip tops of marshmallows in chocolate. Tap off excess chocolate (you can let a little drip down the marshmallow), then place on a foil lined baking sheet.
Swirl tops of graham cracker quarters in chocolate. Gently tap off excess, then transfer to baking sheet.
Chill graham crackers and marshmallows until chocolate is just set, about 5 to 10 minutes.
Once chocolate is set, thread 3 marshmallows on an 8-inch skewer. Repeat with remaining marshmallows and other skewer. Set aside.
Cut two mini slices of pie (about 1.5-inches at the widest end). Set aside.
Place ice cream and milk in a blender, then blend until combined, stirring a couple times to incorporate ingredients.
Divide milkshake between two mason jars.
Top milkshake with a generous amount of whipped cream. It should rise above the glass' rim by about 2 inches.
Insert two chocolate-covered graham crackers (one in front of the other), slightly angled away from the marshmallows.
Top freakshakes with a mini pie slice, resting it on rim of the glass and the whipped cream. Garnish with a straw.
Serve freakshakes immediately. Enjoy!