My OGGZ is looking for an adapter

What is an OGGZ?
It looks like a big egg and it changes colors.
It is just for fun.

But my OGGZ wanted DC7.5V through an AC adapter of 120V.
Norway uses 220V.

My knowledge of electricity is extremely basic, but in the two stores I visited in Moss, I could not find a suitable adapter. In one store the saleswoman said that she was not allowed to sell such an adapter in this country, but that you could buy one at the airport!

Somehow I feel the solution should be much simpler - an adapter where 220V AC comes in from the wall and 7.5V DC goes into the OGGZ.
Wrong?

Problem solved!
Thank you, Gena, for sending me back to the shop to buy the adapter!