T-Rex: Let's say that there are a variety of universes - real and simulated.

T-Rex: However, given the nature of reality, there can only be a SINGLE real universe!

T-Rex: Therefore, since everyone in a simulated universe must believe they're in the single real universe for the simulation to have any value, it follows that the overwhelming odds must be that OUR universe is a simulation! After all, what are the odds that WE'D be in the one real reality?? And given that conclusion, how can we trust anyone or anything - even ourselves! - to be real??

Utahraptor: You can't, really!
T-Rex: ...Wait, what?

Utahraptor: If you accept your premises as true, then the conclusion follows. Though I'd argue that it doesn't really matter, since our universe is "real" in each way that matters - except maybe one, which we can't even test for. Should Mario NOT save the princess, even if he realizes he's in a video game?

T-Rex: That's true. Mario SHOULD absolutely save the princess!
Off panel: Thank you.
T-Rex: But also, Waluigi should get to save Wario.
Off panel: Absolutely.
T-Rex: And also Birdo and F.L.U.D.D.
Off panel: Yes, no-one has ever disagreed with this sentiment