Fabbi theDuck

Fabbi_theDuck is a boss in The Secret Place that spawns after all YouTubers place their block into their respective pedestals. Fabbi also appears in The Boss quest.

Quest Boss Fight
Upon the start of the quest, players are given swords. Four monoliths will sprout out of the ground, then a box that explodes, revealing Fabbi. Fabbi employs explosive pumpkins, flaming ducks, homing tacos, and dinosaurs to kill players. Once killed, Fabbi will drop around 14 bread. All players that complete the quest will receive 100 gold and 10 bread.

The Secret Place Boss Fight
YouTubers begin the fight by placing their blocks and visiting a stone structure behind the shrine. Once text on the structure has appeared and finished, the dot of the giant question mark will turn into Fabbi. All players in The Secret Place will get a sword to fight Fabbi with. Fabbi will deploy devices to kill players, such as a taco that tracks players and kills them. Once Fabbi is killed, the stone structure will reveal a button that is labeled "Click To Update Game".

Trivia

 * This boss is a reference to Fabbi, a BABFT YouTuber, who really really loves bread.
 * Fabbi's displayed rank in Build A Boat For Treasure is "Duck".