Well, it does make sense that Mutavault would be there, since the slivers would be back in M14. I remember the first time I saw one of the returns of slivers, which was way back during the release of Legions in the Onslaught block. From MTGS user TK-421 (these are obviously not the M14 versions of the cards though. They're just there for those who are not familiar with the cards.): "... Mutavault and Shimmering Grotto are in."
Three...
