It's better if I tell you right away, so we can mourn and move on together. Dog Mendonça isn't actually a dog, and the game doesn't revolve around pizza. I know, I'm disappointed too. And hungry. You cannot mention pizza and then not deliver. Sigh.
What The Interactive Adventures of Dog Mendonça & Pizzaboy [official site] actually is: a comedy point-and-click adventure with gorgeous hand-drawn environments and animations, about investigating cases dealing in the occult. It's out now on Windows, Mac and Linux, and there are supernatural ways to get a demo.
Dog Mendonça & Pizzaboy is an original story set in the universe of the graphic novel series of the same name. If that doesn't help you, then let me tell you that, despite appearances, the game largely tries to be funny more than scary or creepy. As in this trailer:
Alice found it a "weird and quirky and pleasant thing" when developers Okam Studio took a demo to Kickstarter in 2014. The original links are dead, but you can obtain it without performing dangerous rituals or summoning the dead, as a kind soul (surely a haunted soul!) uploaded the whole thing on Archive.org. Keep in mind, though, that the demo is more than a year old, so quite a bit may have changed since then.
My own opinion is slightly more negative: its over-reliance on self-aware and 4th-wall-breaking jokes, such as the one in the trailer, became tiring, if not grating, very quickly. Just in the first few minutes you are told that you can't possibly have heard a scream because they don't have the budget for that kind of sound effects; and that to solve the case you need to take everything you find in the environment and combine it with everything else, with no rationale, until you find a solution, because that's how point-and-click games work.
So, your mileage may vary with this one, depending on your sense of humour. Or maybe I'm just grumpy about the lack of pizza.
The Interactive Adventures of Dog Mendonça & Pizzaboy is available on Steam, for £15.99/$19.99/€19.99, with an additional 10% launch discount until March 10th. It's on GOG too, though only for Windows now.