Buy a box of cupcake mixture (or some plain, ready made cupcakes), chocolate and vanilla frosting, tubes of decorating icing in as many creepy colors as you wish, a packet of butter cookies, roughly crushed unsalted peanuts, cornflakes and dark chocolate chips.
Cover one half of the cupcakes with vanilla frosting. Open up the packet of butter cookies and break each cookie into the irregular shape of a Halloween ghost. Stick one ghostly cookie into each vanilla cupcake, then cover it in vanilla frosting. Once the frosting has set, draw ghost-like faces on the cookies with the decorating icing of your choice.
Cover the other half of the cupcakes with chocolate frosting. Melt the dark chocolate chips in a bowl and add the crushed peanuts and cornflakes to the mix. Top the chocolate frosted cupcakes with the mix, and get creative by fashioning different kinds of creepy crawlies, bugs and spiders.