Quibble

"Soaring high above, Quibbles are able to spot and collect resonant rocks with which to build their clever keyboards. This happens only occasionally of course, when the two Quibble minds are able to agree on a single purpose."

Description
The Quibble resembles a swan (or similar bird) with two heads - one with a purple crest and one with a green crest. It sits in a small circular pond, surrounded by a ring of five black and eight white stone tiles, arranged like the keys of a standard piano keyboard. It plays the keyboard by striking the tiles with its beaks.

Song
The Quibble's contribution to an island's song is the sound of a piano. Each head is responsible for playing the notes on its own side of the instrument. The head with the purple crest plays the lower notes, while the head with the green crest plays the higher notes. This is true even if the monster is flipped visually.

Breeding
The Quibble can be bred by combining an air-element monster and a water-element monster. Possible combinations include:
 * Tweedle and Toe Jammer

On Shugabush Island, the Quibble must either be purchased with diamonds or teleported from any other island it is found on (not including Gold) once it reaches level 15.

Earning Rate
Earning rate is in coins per minute.

Maximum Income
Each monster has a limit to how much income it can hold at a time. Increasing the monster's level increases the limit.

Feeding Monsters
Each monster needs to be fed four times before it reaches the next level. Increasing the monster's level increases the coins earned per minute, as well as the maximum coins earned. The food per level is the same for all double element monsters and can be found in this article.

Likes
Every monster has different things that they like. For every unique object that they like that's placed near the monster, the monster's happiness will increase by 25% (in other words, placing two of the same liked item near a monster will still only increase happiness by 25%).
 * Mammott
 * Scups
 * Trumplite
 * Fossil-osaurus
 * Castanevine

Strategy
Some items to take into consideration when designing your island by strategy are number of beds for the monster, rate of income per bed, max income per bed, and time for max income to be reached. The income below is for 100% happy and level 15:

Name Origin
The verb "to qubble" means to argue insistently about  an irrelevant subject, much like the namesake monster is said to do.