I think more likely he will play e4 and we'll get a Sicilian...
Should Carlsen go for the Orangutan tomorrow?
More likely sure, but think about Carlsen's position: a draw with white wins and a loss wouldn't be the end of the world (although a clean sheet is pretty). Chances are very slim that he'll be able to play anything he wants without immediate dire consequences in a WCM again. I say go for it. Play the Halloween Gambit.
lol...I want him to play Benko Opening 1.g3 .
Much less exciting. He played the Réti KIA in the first couple of games as White, and 1.g3 would just lead to a transposition of that, almost certainly.
A Catalan would be nice, and perfectly appropriate for a WCC level game, and a Reversed Dragon could be quite cool if they play according to Dragon theory for a while. Magnus has played the Dragon (itself, not reversed) 6 times in serious games, if I recall correctly, so such is not unthinkable. I certainly wouldn't bet on it, though ;)
Anand won a very nice game in 2008 with black against Carlsen in the open Catalan I believe. That pawn sac to obtain the centre always gives exciting play. Of course Magnus is lot stronger now than he was in 2008. Maybe time for revanche?
!
He has three games to get half a point. He'll manage.
He is in the extremely luxurious position to having the option to play any opening there is - in a World Championship match.
It might be insulting to Anand, but if you forget that part, how awesome would it be to see a crazy surprising no prep wild clublevelopening but high class struggle?!
Think about it.