I don't know if I would say this scene scared me, but it was a really great and tense scene. Around probably halfway in the movie Annihilation, one woman from the group is killed by a bear, and among the survivors, one of the women becomes extremely paranoid because of the crazy body horror stuff that's happening. She ties the others up in chairs to interrogate/kill them. From outside the house, the paranoid woman hears the voice of the friend they thought were dead, and they go to check, but she instead finds a bear with an exposed skull who tears her apart. The skull bear then proceeds to walk inside and find the other women women helplessly tied to the chairs. When the bear opens its mouth, the voice of the dead friend comes out as if she's somehow still alive as part of the bear, and the voice screams for help.