At what point is that app even allowed to exist!?
Maybe the person got permission although that is doubtable.
I’m 100% certain that Nintendo would not allow jpeg artefacts to be visible on the google-image-stolen icons in the app.
Nintendo would also NOT call it iMario.
Nintendo would never release a sound board of mario sounds… Just 6 or 7 sports games featuring him and other less popular nintendo characters.
Not even if hell freezes 
Mario only exists in a single game thats not on a nintendo console and thats a pretty crappy luigi crossover wanna be jump’n’run on the pc …
don’t see why one would need any kind of permission. iMario as name does not violate anything (mario is a common italian and german name). If the assets aren’t rip offs but just mario inspired, then thats no violation too.
And for the story, there is no way to steal anything as the basic story behind mario is as old as mankind.
I believe you could claim that he’s damaging the reputation of the IP. You don’t need any legitimate grounds for a lawsuit, that’s only necessary if you plan on winning it.
In Nintendo’s case, some paperwork would probably be sufficient.
Because it’s obviously ripping off Nintendo’s IP. They even went after Great Gianna Sisters way back when, which was only a Super Mario clone and not directly ripped stuff like this is. If Nintendo was aware of this, which they clearly aren’t ;), it would be pulled by now.
–Eric
Being in the same market counts for a lot when something is trademarked. While Mario is a common Italian name, you could argue a trademark case if you were the first “Mario’s Spaghetti Shop” in town and another guy opened a shop called “Mario’s Linguini Shop” there can be a cause for confusion and damages. Although, “Super Mario’s Plumbing” would likely be OK as they are in different industries. Even if a name or mark was not trademarked, first-use also counts for a lot.
Making a game using a character with a name and appearance so similar to one that is trademarked that it is uncanny is treading into some very dangerous legal territory.