Yool

"Note: Yool can only be bred or purchased until December 26th.  Any Yools on your Cold Island at that point will stay unless you sell them.

"Towards the end of the year, the plump and pleasant Yool schedules a relaxing sojourn on Cold Island.  Its arrival is heralded by the jingle bells dangling from its antlers, and the booming resonance of its voice.  Just being near a Yool produces feelings of peace and joy, so the other monsters always try and convince him to stay the whole year round."

Song
The Yool sings "Ho Ho Ho Ho" in a resonating baritone voice, and also shakes its head quickly to jingle the bells on its antlers.

Breeding
The Yool Monster can only be bred for a limited time during the Christmas season. Possible combination(s):
 * Deedge and Thumpies

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.

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%).
 * Thumpies
 * Crumpler Tree
 * Piney Tree
 * Deedge

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: