Drudge Ghoul
The Drudge Ghoul is a battle pet dropped by The Lich King in Icecrown Citadel on Normal mode (10 or 25 player), learned by using {item:inv_misc_herb_ancientlichen} Drudge Remains, and is part of the Raiding with Leashes IV: Wrath of the Lich King achievement.
The Drudge Ghoul is a battle pet dropped by The Lich King in Icecrown Citadel on Normal mode (10 or 25 player), learned by using 
Drudge Remains, and is part of the Raiding with Leashes IV: Wrath of the Lich King achievement.
Guide awaiting review
Enter Icecrown Citadel Normal
Set Icecrown Citadel to Normal difficulty (either 10 or 25 player) and make your way to The Lich King. Both Normal sizes share the same loot table for this pet, so either works.
Defeat The Lich King
Defeat The Lich King on Normal mode — the Drudge Ghoul is confirmed to drop exclusively in Normal difficulty, not Heroic. The Dungeon Journal confirms this drop is tied to Normal mode only.
Loot Drudge Remains
If the pet drops, loot Drudge Remains and use it to add the Drudge Ghoul to your collection. Reset and repeat on additional characters each week to improve your odds.
Tips
The Lich King has a separate Heroic-only pet called the Wicked Soul — if you are farming the Drudge Ghoul specifically, run Normal mode only.
