That's terrible!

好恐怖！

How awful!

可怕噢！

That's horrible/dreadful!

好可怕/吓人！

What a nightmare!

真是恶梦一场！

How terrifying!

吓死人了！

That's scary!

真令人害怕！

How frightening!

恐怖噢！

How creepy!

真令人毛骨悚然！

That's spooky!

阴森森的！