Do the items i build change? I hear people say you should build tank when you're behind but that's already what i'm doing. Do i just try to land my CC in better locations based around how my team is behind (Such as picking off stragglers like the jungler or a bad split pusher) so my team can slowly catch up?
Look for opportunities to punish the enemy team when they get too cocky, amumu is useful even if he gets behind. Just make sure when if your making a play/ going in, that you have people around you to follow up, otherwise your just suiciding vs a more fed enemy team.
I build him as a tank regardless too, but when also usually get behind the enemy jungler anyway, even when I win the games. Just keep in mind that his stuns, especially his ult, is helpful at all stages of the game. Until then, just farm what you can until you ult is ready. Remember that you don't pick Amumu for 1v1 fights.
If you are behind as Amumu, farm hard. Once he has 3 items, he becomes a problem for the other team.
