Perpetual Timepiece

Oracle Text

T: Put the top two cards of your library into your graveyard.

2, Exile Perpetual Timepiece: Shuffle any number of target cards from your graveyard into your library.

Card Rulings

9/20/2016 You can activate Perpetual Timepiece’s second ability with no targets just to shuffle your library. If you choose any targets and they all become illegal targets, the ability won’t resolve and you won’t shuffle your library.