[18] A Recipe for Death - Part III:

Bring 6 samples of Lake Creeper Moss, 6 samples of Lake Skulker Moss and a Hardened Tumor to Master Apothecary Faranell in the Undercity.

Apothecary Renferrel: According to Berard's Journal the moss from Lake Skulkers and Creepers might prove useful for our quest to brew a new plague. Those beasts dwell on the islands in Lake Lordamere to the east.

He also mentions a very rare Hardened Tumor that he discovered on a Vile Fin murloc. Apparently the tumor is so rare Berard was only able to obtain one.

Collect samples of the moss as well as the rare hardened tumor and take them to Master Apothecary Faranell in the Undercity.

Master Apothecary Faranell: What brings you back to the Undercity, Yohaan?

Master Apothecary Faranell: Such a blow to the Royal Apothecary Society to lose Berard. But through your hard work and Apothecary Renferrel's diligent research Berard's studies will still be useful to The Dark Lady's plight.

We are on the cusp of something great here, Yohaan. If you were not so skilled in the ways of combat I would try to recruit you for membership in the Society.