Mushroom Castle Bosses

Mushroom Castle bosses at a glance

Where	Mushroom Castle (the Blocked Entrance at The Last Castle Tower)
King Pepe	Solo, 20 minutes; one of three Yeti and King Pepe bosses (120,000 HP)
Prime Minister	Party of 1 to 3, level 30+, 10 minutes (12,500 HP)

The Mushroom Castle bosses belong to the Mushroom Castle story. The quests themselves are in Mushroom Castle Quest Guide.

King Pepe and the Yeti Brothers

During "Stop the Wedding" the Blocked Entrance offers "Enter to fight King Pepe and Yeti Brothers". You go alone; 20 minutes.
Each time you enter, one of Grey, Gold or White Yeti and King Pepe appears (level 35, 120,000 HP). They summon Helmet Pepes and Royal Guard Pepes.
When all three have been defeated for the quest, leaving the hall gives you the key to the Wedding Hall.

Later in the story the door leads to the Wedding Hall. Once a player on "The Story of Betrayal" is inside, the Prime Minister rises (level 38, 12,500 HP, 800 EXP) and the 10-minute clock starts. After the story, the Blocked Entrance offers a rematch.
Drops: Dark Token, the Royal Seal of the Mushking Empire (60%), arrows (30%), potions, ores and scrolls.