DD5 has put this in her list to Santa. I have no idea what it is. I probed her a bit and she said it’s either a My Little Pony or a unicorn that is in a shell you can open. She said she saw it in a shop but can’t remember which one.
It’s not hatchimals in a seashell and it’s not the My Little Pony seapony song toy - I thought I’d cracked it when I saw this but she said it’s not it, it’s definitely a shell you can open 
She may well have imagined this toy up but if anyone knows what she might be talking about I’d be very grateful!