YOU SAID:
My cat is lost, nevermind he´s sleeping in the bathtub
INTO JAPANESE
私の猫は迷子になりました。
BACK INTO ENGLISH
My cat got lost.
INTO JAPANESE
猫が迷子になりました。
BACK INTO ENGLISH
The cat got lost.
INTO JAPANESE
猫は迷子になりました。
BACK INTO ENGLISH
The cat got lost.
That didn't even make that much sense in English.