A Tome Entombed - The Witcher 3

While in the passageways underneath Novigrad (I've been there as well, and don't recommend them as tourist destinations - if the stench doesn't get you, the monsters will) Geralt met a scholar who was excavating in search of traces of long-lost cultures. The professor asked Geralt for help removing the lid from a certain ancient sarcophagus.

Geralt decided to promote the advancement of knowledge and help the scholar open the sarcophagus. Instead of the expected withered skeleton, inside lay a fully fleshy vampire. He was not hostile at first and merely asked for a bit of peace and quiet while he finished his rest. The scholar, however, had no intention of respecting this wish. Geralt could not stop him and... the vampire lost his temper and attacked Geralt and the bothersome professor. Whether he wanted to or not, Geralt now had to end its life.