Brainless enemy tank team, usually tank teams are pretty much unstoppable if they know how to...you know...tank?
Every team fight I got completely ignored (while I was still a glass cannon) even when my skills were on cooldown and the most magic resist they had throughout the game until the very last team fight was 1 negatron cloak... on 1 person XD.
When the last team fight happened, they finally had a little (barely, lol) more magic resist and chose to focus me, but I already had ~700 AP and some survivability.