Pour the gelatin into a bowl. Add the food color too if using clear gelatin.
Heat the lychee syrup to simmering and pour over the gelatin. Stir until the gelatin is dissolved.
Pour in the gin and lime cordial, stirring as you pour.
Pour the gelatin mixture into glasses. If the gelatin solidifies too fast at this point, heat gently in the microwave until pourable.
Push an olive slice in the natural groove of each lychee. Not too deep. You want the olive to be visible.
When the gelatin is barely set, carefully drop a lychee into each glass.
Serve the jello shots with floating eyeballs chilled.