In my homeland, there is a famous fairytale in translation called "There is a green oak by the sea":

There is a green oak by the sea;
There is a golden chain upon the oak:
And night and day a wise cat
Walks around upon the chain;
It goes to the right -- and starts to sing,
It goes to the left -- and tells a story.

There's magic there: a goblin wanders about,
A mermaid sits among the branches;
And the tracks of unseen beasts
Are marked upon unknown paths;
And a hut stands there on chicken legs
With neither windows nor doors...

I adore the cat-chain line and, as you can see, I illustrated the mermaid part. Hope you like it!
... I also specialize on drawing nagas/mermaids/adgonians/dragons/lizards/etc so consider commissioning me ;0