Heat the oven to 180°C/350°F and line two baking sheets with parchment paper.

Beat the softened butter, granulated sugar, and packed light brown sugar until creamy, about 2 minutes. Add the egg and vanilla extract, then beat until incorporated.

Whisk the flour, baking soda, and fine salt in a separate bowl. Add the dry ingredients to the butter mixture and mix just until no obvious streaks of flour remain.

Stir in the semisweet chocolate chips. Portion the dough into roughly 1½-tablespoon balls and place them several centimeters apart on the prepared baking sheets.

If the dough feels very soft or tends to spread, chill the shaped dough for about 30 minutes. Bake for 10–12 minutes, until the edges are set while the centers still look slightly soft.

Immediately press one small chocolate candy into the center of each hot cookie. Let the cookies cool on the baking tray for 5 minutes, then move them to a wire rack.

Once the cookies are cool enough that the candy will not slide, attach two candy eyes to each chocolate body using small dots of melted chocolate.

Transfer the remaining melted chocolate to a piping bag or small zip-top bag with the corner snipped off. Pipe four legs on each side of every candy body, then allow the chocolate to set before serving.