Quest:Blood of Morphaz

Objectives
Kill Morphaz in the sunken temple of Atal'Hakkar, and return his blood to Greta Mosshoof in Felwood. The entrance to the sunken temple can be found in the Swamp of Sorrows.
 * Blood of Morphaz

Description
Now the last part, the second cure.

The green drake Morphaz is known to be immune to all forms of poison and disease -- many druids died to bring us this information. There is no doubt his blood is potent for our needs.

A courier from the Cenarion Circle will take the parts you have already collected while you gather the last. Summon your allies and seek out the drake's lair in the sunken temple of Atal'Hakkar. Bring his blood to Greta Mosshoof in Felwood.

Rewards
You will also receive:

Progress
Do you have the blood of Morphaz?

Completion
You have slain Morphaz and carried his blood to us... I can hardly believe this good news!

We will combine the ingredients at once and begin healing the trees and creatures of Felwood. It will take a lifetime to undo what has happened here, but you have given us the means to do it.

Triva
The line "many druids died to bring us this information" in the Quest Description is a clear tip of the hat to Stars Wars: Return of the Jedi, recalling the scene of Mon Motha telling the Rebel Alliance of the second Death Star's fatal weakness, claiming that "many Bothans died to bring us this information."