Lay fifteen 2-ounce plastic ramekin cups out on a baking sheet. Set aside.
Guinness Layer
Pour gelatin pouch into a small mixing bowl or measuring cup with a pour spout. Add 1/4 cup cold Guinness to the bowl and stir. Let stand for 3 to 5 minutes.
While the gelatin absorbs into the beer, heat the rest of the Guinness bottle in a saucepan over medium-high heat until simmering.
Pour the hot beer into the bowl and whisk until the gelatin is completely melted. Pour in whiskey and stir to combine.
Pour Guinness mixture into plastic cups, filling each one about 1/2 full. Transfer to the fridge and chill for 1 hour. (The jello should be set, but not firm.)
Irish Cream Layer
Pour gelatin pouch into a small mixing bowl or measuring cup with a pour spout. Add 1/4 cup cold Irish cream to the bowl and stir. Let stand for 3 to 5 minutes.
Meanwhile, heat 1 cup Irish cream in a saucepan over medium-high heat until just simmering.
Pour the hot Irish cream into the bowl and whisk until the gelatin is completely melted. Add sugar and whisk until sugar is melted.
Pour Irish Cream mixture over the Guinness jello until each cup is almost full. (You want to leave a little room so you can put the lid on later.) Return jello shots to the fridge and chill for about 2 hours, or until completely set. Top each cup with a lid and keep cold until ready to serve.