YouTube Glitch or Hacker?: Post Edition

Hey peeps. So, I was in my history on YouTube, and I went to the "Comments on videos" section. Because, I wanted to check them out. But, I noticed something weird. I noticed like over 10 comments that I don't remember making. I had my phone next to the laptop on the desk, so I grabbed that and filmed a video. Here are a few Q&A'S about this situation that you might be curious about:

1. How did it happen?I don't know. I'm thinking 50% pf it is a YouTube glitch, and 50% of it is a hacker commenting as us.

2. Us???
Yes, I said us because not only did "I" comment on these videos, but a ton of other users did as well. And some even commented the same words as I did! Creepy!!

3. What are the videos that you commented on?
I commented on several gameplay videos by this channel called "Live Play". And I was also subscribed to this channel!!

4. Proof of evidence.

Even though I deleted all of my comments that were on those gameplay videos, I screen captured these comments before I went and deleted all of them. 

And proof that I was subbed to "Live Play":

Yeah, pretty weird and scary. Not even sure why this happened in the first place.  And I'm also not sure why I haven't found this out until today. Hopefully you won't have to deal with this.

Video regarding this glitch