Buffy [Drained Man Turns]

Buffy the Vampire Slayer - Ep 46 [Helpless]: To prepare Buffy for her unknowing test, the Watchers Council have restrained a notorious vampire name Kralik for her to have to fight without her Slayer powers. However Kralik manages to free an arm from one of his restraints and tricks one of the caretakers, Blair, into getting closer so he can grab and drain him of his blood. Blair soon turns, his body morphing to heal up the bite wound Kralik gave him.

Example of:
Vampire Hickey