Sprinkle the gelatin over the cold water in a small bowl and let it sit for 5 minutes to bloom.
Warm the mango nectar and honey in a saucepan over medium heat, stirring until the honey dissolves completely.
Remove the pan from heat and stir in the bloomed gelatin until it melts into the liquid.
Add the lime juice and mix well.
Pour the mixture into a brain-shaped silicone mold, filling each cavity evenly.
Refrigerate for at least 4 hours until fully set.
Gently flex the mold to release the shots and place them on a serving plate.