YOU SAID:

One time I had a dog but I got him TOO fat and his heart exploded

INTO JAPANESE

あるとき犬を飼っていたが太りすぎて心臓が爆発した

BACK INTO ENGLISH

One time, I had a dog, but I was overweight, and my heart exploded.

INTO JAPANESE

あるとき、犬を飼っていたが、太りすぎて心臓が爆発した。

BACK INTO ENGLISH

At one point, I had a dog, but it was overweight and my heart exploded.

INTO JAPANESE

ある時、私は犬を飼っていましたが、太りすぎて心臓が爆発しました。

BACK INTO ENGLISH

At one point, I had a dog, but it was overweight and my heart exploded.