I think you’re looking at our “Count to 1 Trillion- OFF Topics and Hijacks Welcomed!!!” thread. It’s one of our “fun & games” threads. All you do is copy the number of the most recent post in the thread, post a reply pasting the number you copied and increment it by 1, then submit it.
The thread serves no real purpose other than wasting your time. However, users post numbers almost daily, making it show up in your subscribed threads. If it’s annoying to you, unsubscribe to that thread and it will no longer appear in the list.
I guessed at this as there was insufficient information provided. If this was not the solution, please post again with more details.