Furry Warts are a furred ball-like soot settling in roof of Xandred's Junk. They attempt to be annoying by descending from the ceiling of the ship's interior and repeating people's words while giggling.
The Furry Warts in Xandred's ship are revealed to have been partial to Dayu, as some time after Dayu defected, when Xandred kicks one off into a gap to the 'real world' it lands near her and tells her in fully spoken English that it has missed her. This one Furry Wart becomes Dayu's companion. This Furry Wart is still able to tell Dayu what is happening on the ship, despite neither of them being on it at the time. Master Xandred once tried to teach the Furry Warts to mimic Dayu's Harmonium song, which failed to occur.