Here is the tutorial for our Mermaid Socks and Hat
Mermaid Stitch
SL3 WYIF Slip 3 Stitches with yarn in front from left to right needle as if to PURL
K3TOG with strands: insert the tip of the right needle from below under the two strands, then pull and put them on the left needle, then knit them with the next knit stitch.