Yorick doing MASSIVE damage

Okay so I played this game and I didn't do so well but that's besides the point. There was this 15/0 Tryndamere on the enemy team. He got a pentakill. He had the most kills on his team. Obviously he SHOULD have done the most damage, but I mean sometimes you're the most fed on your team and you don't do the most damage but you've still managed to do a pretty large amount of damage. This enemy Yorick, who was 6/3, did CRAZY damage. Tryndamere did 11.8k damage to Champions. Yorick didn't just do double that, triple that, or even 10 times Tryndamere's damage: he did 356.1k DAMAGE! It's crazy! I don't know if this is a glitch or not, but it's weird because I was able to 1v1 the Yorick a few times. Here's the match history: http://matchhistory.na.leagueoflegends.com/en/#match-details/NA1/2149662032/229441229?tab=overview