Grumpyre

"Another of the mysterious Ethereals, you can never fully tell what kind of mood the Grumpyre is in. Thanks to its shifting eyes and mouth as it gurgles forth its song, it might appear sad when really it's happy, or afraid when it's actually having a blast. This makes sense, since it embodies the essence of shadow - always a bit obscured, and able to unnerve even the most intrepid of monsters."

Description
The Grumpyre joined the song on August 19, 2013. The monster resembles a gray-black bat creature surrounded in a cloud of smoke. He has four wings, two arms, and goes cross-eyed at random sometimes.

Song
The Grumpyre sings "boom-shicka-la-shicka" in a harsh whispering  voice. He does this repeatedly for his part in the song.

Breeding
The Grumpyre can be bred using a combination of one four-element monster and one three-element monster. Possible combination(s): ​There is roughly a 1% chance of breeding this successfully. It is uncertain whether some combinations work better than others. According to statistics, doing 70 attempts gives you a 50% chance of successfully breeding a Grumpyre.
 * Deedge and Congle
 * Deedge and Bowgart
 * Deedge and Spunge
 * Deedge and Thumpies

Coins
Earning rate is in coins per minute.

Shards
Earning rate is in shards per hour.

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. The food per level is the same for all Ethereal element monsters and can be found in this article. With the Ethereal Island update, Ethereal monsters can achieve level increases to level 15, and may be placed on Ethereal Island instead of Gold Island.

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%).
 * Maw
 * Saggle Tree
 * Dragon Tower
 * Bass String Bridge
 * Bloofi 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 10 :