Denalan at Lake Al'Ameth wants you to collect the Gargantuan Tumor from Oakenscowl.
In a cave along the southern bank of the lake, a timberling named Oakenscowl is spreading corruption to all the creatures that make Lake Al'Ameth their home.
I dared not get too close, but even from a distance, it is obvious: Oakenscowl is being poisoned by the largest tumor I have ever seen... I would call it gargantuan, even.
[player], you have already done much to aid my efforts, but I ask of you one more task. Hunt down Oakenscowl and collect the tumor; remove this source of corruption from my home.