Silas and Stefan in “Unfinished Business”

Silas

[in Elena's form] Don't bother. I'm not in there anymore.

Stefan

Silas. You were stone. They saw you. The spell worked.

Silas

That's the funny thing about spells. They're bound by nature, and nature demands balance, so every spell has a loophole. The spell that turned me to stone was bound by a witch, a living witch, so when that witch died, the spell broke.

Stefan

Bonnie. Bonnie's not dead.

Silas

Doesn't matter, does it? And here's where the mystery of me comes full circle. I created the immortality spell 2,000 years ago. I could never die, so nature needed to find a balance, a version of me that could die. A shadow self; a doppelganger.

Stefan

So this is finally your real face? You're another one of them?

Silas

Not exactly. Hello, my shadow self.