YOU SAID:
Eighteen crows are scary.
INTO JAPANESE
18のカラスは怖いです。
BACK INTO ENGLISH
18 crows are scary.
INTO JAPANESE
18頭のカラスが怖いです。
BACK INTO ENGLISH
I am scared of 18 crows.
INTO JAPANESE
私は18頭のカラスが怖いです。
BACK INTO ENGLISH
I am afraid of 18 crows.
INTO JAPANESE
私は18頭のカラスが怖いです。
BACK INTO ENGLISH
I am afraid of 18 crows.
That didn't even make that much sense in English.