"Backseat Gamer" damage?

Didn't take a screenshot of it. I figured it was something that happened to others as well, but I've searched for it and have found nothing yet.

When checking the damage to see what killed me, one of the entries from a Darius player had no icon on the left (just a blank space), showed 348 physical damage (or something close to that), had no skill listed at the top, and had "Backseat Gamer" under the damage. I have no idea where this damage came from and have found no reference to it anywhere as of yet.

If this happens again, I'll take a screenshot of it I guess.