Hearing werid sounds in game, not sure if its a bug or intended

Played a game as trundle during a game I believe I heard voice overs that weren't trundles or any other champion in game. It may have been old trundle's voice over but I'm not sure since I know he was changed before I started playing league. Next game I was playing Vladimir and I definitely heard a voice that didn't belong to any champ I could think of. I don't know if its a bug but the only other thing that came to mind was it being a champion teaser similar to what kindred had before release. The only thing I remember clearly was the voice saying "we/I are watching." Just wanted to post this to see if anyone else has experienced it or could know more.