Timelock, the Ever-Living

Flash, deathtouch, hexproof
Instant and sorcery spells you cast have buyback {u/r}{u/r}{u/r}.
Whenever you buyback a spell, you may exile it, pay {u}{b}, and sacrifice a creature. If you do, take an extra turn after this one.
You may cast Timelock from exile or from your graveyard.