I received an email from my team-mate cheering us on for a big race we are competing in this weekend and she used the phrase ばっちこい! I googled ばっちこい and the results say that it t …

I've ran into あいつ a few times in sentences and it seems to mean he/she. Is this correct?

Hey everyone, I was wondering what the つーの in the phrase "ありえないつーの" means. When do you use つーの? What other words or phrases commonly end this way? Thanks!