If you don't want to spend upward of $100 on a Halloween costume [1], we don't blame you. After all, you usually only wear it for one or two nights. Instead, survey your own makeup stash and you'll surely find everything you need to create a costume [2] in a snap. In this case, you'll need some ocean-toned eye shadows and your fishnets for a mermaid look with a twist.

Based on Ryn from Freeform's Siren, this tutorial will have you asking, "Ariel who?" It's equal parts creepy, glam, and cool. Start with your normal foundation routine, apply cool-toned eye shadow on your lids to the brow bone, then add highlighter to the high points of your face. We recommend using one with a green cast to it, like Wet N Wild Fantasy Makers MegaGlo Highlighter in Moonlit Gleam [3] ($5). Next, it's time to create the fish scales, which you can do one of two ways: Wet N Wild makes stencils [4] ($2) that are easy to apply, or you can opt for fishnets. Yes. Fishnets on your head. We don't make the rules here. It looks bizarre, but it works like a charm — trust.

Take a densely packed shadow or blending brush and start pushing a gray- or slate-colored pigment into the fishnets. Blend shades like blue and green as well so they fade into each other. Make sure you're picking up a lot of pigment or shadow on the brush and pressing into the skin; fluffy brushes tend to diffuse the product and won't make the scales look as defined.

From there, add your favorite sea-inspired lipstick, put on some lashes [5], and get ready for the final step: fake blood. You'll want to spritz it around your mouth like you've been feeding — that's what makes it creepy. Then you're ready to attack, er, casually sit on a rock and sing about wanting to be where the people are. Yeah, that.

Be sure to subscribe to our friends at Freeform [6], and gear up for the third season of Siren, which is currently in the works. [7]