摄魂怪的出现让整个房间变得冰冷而绝望。

The presence of a ___Dementor made the entire room cold and full of despair.

那个悲观的朋友就像一个摄魂怪，每次聊天都让我心情低落。

That pessimistic friend is like a ___dementor, making me feel down every time we talk.