Riff

"Riffs are masterful musicians. Very little is known about these complex monsters, but they do have some distinct and unusual habits. For example, Riffs use their flexible toes to select random objects from the ground which they inspect, then eat."

Song
The Riff Monster's contribution to an island's song is playing an instrument resembling an electric guitar. The guitar is not actually electric, nor is it a real instrument: it is another monster who shares a symbiotic relationship with the Riff. The guitar monster can be strummed or picked to produce sounds matching its real-life counterpart.

Breeding
The Riff Monster can be bred using monsters that combine to provide all the elements of Air, Earth, Water and Cold. Easiest combination(s) are 3 element with 1 element monsters. 2 element with 2 element monters can result in the Riff, but have lower chances of success:
 * Scups and Mammott
 * T-Rox and Tweedle
 * Congle and Noggin
 * Pompom and Toe Jammer

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.

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. The food per level is the same for all four 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%).
 * Toe Jammer
 * Bass String Bridge
 * Leafy Sea Dragon
 * Crumpler Tree

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 level 15: