(Meta) Spam bots commenting all posts here with unrelated gifs. I may be wrongly suspicious.

I'm not sure if it is a problem or not but I spotted this on all the most upvoted posts here. They all have a username like : . And most of the time they only post a imgur link, it's always more or less unrelated. Although sometimes it's not obvious because it's a meme reaction gif that could be legitly posted.
It seems to me that it's something that should be regulated because they post imgur links today but could post any other links tomorrow.