This pattern is for the matching doll mermaid tail to the pattern found here:

http://www.yarnspirations.com/patterns/mermaid-sleep-snug...

If you have made the above pattern, then the doll pattern should easily make sense.
However, I prefer to work in the round on the body portion like the shark pattern found here: http://www.yarnspirations.com/patterns/shark-sleep-snuggl...

The pattern for the child tail calls for 4 skeins and this matching doll mermaid tail is made from the leftovers from making the bigger pattern referenced above.

Don’t forget to check out my Samantha Stitches FB page to see what else I create. You may just want another pattern!