You heard me right. this quest is literally about collecting crap. Here's what I know:
The quest begins with the farmer East of Moonglow. There's also a savage bunny in the yard with him, and it will attack you. It's weak, so don't worry about it. (Also drops a green carrot which is unedible). Talk to the farmer, who will complain about something or other and say he needs crap as fertilizer for his farm. The crap can be found as loot off a monster called the Crayma.
I have seen this monster, but only once as someone else was killing it. It spawns in the Elemental Cave a good ways South of Humility, and it's respawn rate is terrible... 6-8 hours from what I understand. Not sure if it is a drop everytime or not, and don't know if it's one at a time or multiples. The person I saw fighting it was using a cu sidhe as well, so pets should be okay on it.
If I remember right, you need 20 crap to complete the quest. The farmer will give you some sort of sword, unsure of the stats. I have also heard rumors that the Crayma has a rare robe drop, with stats similar to a shroud of wonder.
That's all I know, so good luck to all and feel free to add info or correct anything if I am wrong.