the vampire diaries 1x07
Stefan tries to help Vicki deal with her urge to feed, but is unable to control her. At a Halloween party, she attacks Jeremy and Elena, and Stefan stakes her through the heart, killing her. Stefan swears Elena to secrecy so she won't tell Matt and Jeremy what really happened to Vicki. Elena is unable to console the grieving Jeremy and asks Stefan to use his powers to make sure her brother does not remember what happened. When Stefan tells her he is unsure of it working effectively, Damon volunteers to "take away his suffering."