Has this question been asked yet? Is there any reason they made it this way, or was Gamefreak just having fun? It just seems so random. Did they want to use the gyroscope for something other than pictures/holo caster?
I think they wanted to add a new type of evolution into the game, and one that was unique. Also, Inkay kind of looks like Malamar upside down, and vice versa.
If you look closeley, Malamar's head comes from the bottom of its previous evolution.
(It may be a bit confusing)