YOU SAID:

I took the dog for a walk, but I ran into an old buddy

INTO JAPANESE

私は犬を散歩に連れて行ったが、昔の仲間に偶然出会った

BACK INTO ENGLISH

I took my dog for a walk, but I stumbled across an old companion

INTO JAPANESE

私は犬を散歩に連れて行ったが、偶然昔の仲間に出くわした

BACK INTO ENGLISH

I took my dog for a walk, but I stumbled upon an old companion

INTO JAPANESE

私は犬を散歩に連れて行ったが、偶然昔の仲間に出くわした

BACK INTO ENGLISH

I took my dog for a walk, but I stumbled upon an old companion