Inanis, Priestess of the Ancient Ones

Devoid
Whenever you cast a colorless non-artifact spell each player exiles the top card of their library.
If there's thirteen or more cards in exile, if a card would be put into a graveyard from anywhere, exile it instead.
{X}, {T}: Shuffle a spell with mana value X or less in exile into its owner's library. If you do, copy that spell. You may cast the copy without paying its mana cost. The copy is colorless. Activate this ability only if there's thirty one or more cards in exile and only once each turn.