YOU SAID:
The bad cats must be boiled.
INTO JAPANESE
悪い猫を煮沸する必要があります。
BACK INTO ENGLISH
You need to boil the bad cat.
INTO JAPANESE
悪い猫を沸騰させる必要があります。
BACK INTO ENGLISH
You need to boil the bad cat.
That didn't even make that much sense in English.