Here’s a reversible spider edging from Butterick’s 1892 The Art of Knitting, pp.35-36. Cast-on is just 16 stitches. The edging’s header uses 7 of the 16 stitches and there’s a 12-row repeat. I added an extra stitch at the non-header edge for easier knitting and changed the first header stitch to a slip stitch for easier sewing later.
I used DMC pearl cotton for this project. Use any yarn or thread that makes well-defined stitches.

Skills needed: cast on, slip, knit, purl, YO, YO twice, k2tog, p2tog, SK2P and bind off in knit stitch.

Gauge is not important in this pattern. Any block-able yarn/thread will work. Make a swatch to check gauge and appearance.

30 yards of DMC #5 pearl cotton thread will make 10 inches of Halloween Spider Edging at gauge.