I think I got this as part of a software bundle several years ago, although I'm uncertain as to how many years, probably over five. It was a puzzle game with 3d graphics. Cartoonish colors, if not style. In the game, you made your way through the levels with the help of your imaginary friend. I believe the child was small enough to fit through gaps while the monstrous imaginary friend was strong enough to move some blocks. The title was something like Gabba and Yoyo, alright that just brings up results for Yo Gabba Gabba.
I have this lingering feeling that the kid was Spanish or South American, and when reading up on the game, learning that he had difficulties with an alcoholic father, and that one of the theories for the game was that it was him hallucinating in a coma after being beaten, with his monstrous friend reflecting his perception of his father, alternately violent and kind.