so for the last day of the login for the premium you get a chest that says mermaid shell complete set.. I opened the chest and it gave me a bunch of items that i thought were supposed to go into your wardrobe but when i clicked on one of them and then clicked use item it gave me an egg.. is that what is supposed to happen?
i forgot to add that it used all the items when it gave me the egg

Mermaid shells are that combine to provide a prize if you have one of each item in the set in the inventory (like hoe the Sylestopoly pieces work).
In the case of the Mermaid Shells, it's a set of 9 items, and the reward is a (assuming they're running on the same parameters as last year) Sculpting Theme that will be 2v, have a Certified Name, and have 1 guaranteed Lost Grove Wild Restricted Trait


here's the excerpt from last years overview when the items were obtained from Seeking rather than being a single premium login prize:
"Mermaid Shells

New this year are the Mermaid Shells! Collect all 9 and combine them to receive a very special Summer Festival Themed Pet! Each Themed Pet created from Mermaid Shells will be a 2-Visible Sculpting Themed Pet (excluding Restricted and Aged) and will come with a guaranteed Restricted Wild Trait. Additionally, each Pet will come with its very own Certified Name!"

Thank you i got an Ocean Odyssey Lupora with a certified name think it said 2 or 3 vis.