Remove gel dessert from plastic cup and place into a microwave-safe bowl; mash with a fork. Heat in microwave on low in 10-second intervals until melted, mashing each time with fork, 1 to 2 minutes. Stir peach schnapps into melted gel. Pour into shot cup and refrigerate until set, at least 30 minutes.
ConAgra Snack Pack Juicy Gels(R) are vegan, Jell-O(R) brand is not. It might work with gelatin snack cups, but I have never tried it.
Try any combination of snack pack gel and liquor or liqueur you'd like. Some good ones are
; orange/vanilla vodka; strawberry/apple schnapps; strawberry/coconut rum; cherry/chocolate liqueur; and cherry/amaretto.