Why is Mumu 100 to 0 me ?

It might just be me, but it seems like he is doing more damage? We were both level 10, 12 minutes into the game and i was actually about 80 percent hp after killing Xerath (i was 2-0 here). He brought me to 0 before i could E-Q. Later in the game, with only one damage item he was able not to just tank all my damage (which you'd expect) but bring me 100->0.

I know they mentioned they were worried about Mumu being too strong in this jungle...but my very first game? lol We actually lost the game because people got caught out and they had end game with Vayne, but i'm just curious as to if this is intended. HE didn't even have either of the 2 smites that damage players.

Game is in my match history. I was Viktor, finished 10-5-7.