Gellar's tribute to her late costar echoes a monologue she delivered in the supernatural drama's season 5 finale.

The actress was found dead in her New York City apartment on Feb. 26. Her former co-stars, including Sarah Michelle Gellar and Blake Lively, are honoring her memory on social media.

Dawn Summers on 'Buffy the Vampire Slayer' was magical energy turned human. Michelle Trachtenberg made her everyone's kid sister.