Carlyn Kathlor, Rogue Archer

Double-strike, haste, protection from white
When Carlyn deals combat damage to an
opponent, reveal that many cards from the top of
your library. You may cast any number of instant
or sorcery cards from among them without paying
their mana costs, then you must put the rest into
your graveyard. Each player gains 1 life for each instant or sorcery card you cast this way.