Hmm.. maybe they should make a items to handle this sort of character... oh wait, they do...

Regen is countered with Executioner's Calling
Armor can be countered with armor penetration or more damage.
His movement can be countered with a Frozen Mallet.

Mundo is not op, he is pretty middle to > good
Cleaver misses most of the time when its really needed and that makes him much less powerful
Also, his healklt regen (which is his strenght) is disabled when using burning agony , sou you can only use it in End content properly.
His damage is only average and he needs at least 2 hp armors to be halfway effective.
He is not unkillable by far.
And his ultimate is pretty helpful but not super strong, especially not if they burst you.

And dont complain troll if you never even played 3 matches atleast with him.

Mundo is a lot like Alistar...only he's naturally great at farming at the expense of sucking in team fights.

Just ignore him till his teammates fall...unlike Alistar, he can't really do anything to help them besides Summoner Spells.

Boatloads of HP, crazy regen, near-complete CC reduction, possibly stacked armor and magic resistance...hell yeah he's hard to take down.

Doesn't mean you have to.

Dealing with Dr. Mundo 101:

1) Disable and kill Ashe.
2) Disable and kill Tryndamere.
3) Kill the other two champions they chose.
4) ???
5) Profit

Sometimes when I talk I find things.

Mundo does need a nerf.

A good Mundo and Singed can run around all day and not get ganked unless its 3v1.

By the time a 2v1 can come close to killing Mundo or Singed its been so long he is either at his tower or his entire team has arrived.

I understand they are supposed to be tanks and hard to kill, but the imba thing is that they can do good damage as well.