In what should be used as an example to not believe everything you read on the internet, it seems someone from the Internet Movie Database (IMDB) might be trolling Sony and Nintendo fans at the same time; as a current listing for Sony’s upcoming PlayStation All-Stars Battle Royale lists Mario and his voice-actor Charles Martinet as part of the cast!
If you don't believe me, here's a screenshot of said IMDB page.
Now, before you go jump into conclusions that Sony and Nintendo are sleeping together, do keep in mind that any IMDB Pro user can alter IMDB pages. So, in other words — yes! This is most assuredly a fake!
Aside from IMDB Pro fact, does anyone honestly think Nintendo will just lend out their official mascot to one of their rivals? Why, that's as absurd as Master Chief appearing in Killzone or Nathan Drake being playable in a Halo game! While it's fun to speculate and dream, the fact is, this sort of team-up will most likely never happen — unless one of the companies get bought out by the other, or some absurd deal is struck.
Let's consider this "rumor" debunked before it gets out of hand, shall we?
Source: NeoGaf