It can be literally anything.
Here are just a few ideas: -
An Under the Sea sensory bin
A story of what this mermaids life is like
An outing to the beach to hunt for mermaids
A Mermaid inspired educational activity
A painting of a mermaid
A skirt for your kid inspired by a mermaid tail
A poem inspired by the doll
A cross stitch of a sea scape
The competition will close on the first of July and Hublet and I will choose one winner - we aren't looking for beauty and perfection, we'll be looking for fun, and something that stands out.
The competition will be open to everyone internationally, and non bloggers can enter by emailing their project to Tamingthegoblin [at] gmail [dot] com. I'll do a post the day before the project closes for all non blog entries.
I hope you are as excited as I am. Keep your eye out for full details in the first week of June.