Cirronimbus

This cloud appears once in Angry Birds: Shade's Big Eggventure. The Cirronimbus is protected by 9 orbs on the Island Core of the Center Island of the LLA. It's encased in a glass amber to focus it's power

Thunder
The cloud can produce thunder but only when released or used as energy for a superweapon

Psychic Powers
The LLA (An Archapelago is a group of islands) is held together by psychic force from the cloud. If the Earth's continents formed Pangea in the next several thousand years The LLA would be the only one not formed in Pangea.

Trivia

 * Although not inspired, this resembles a Cirrocumulus species.
 * The gray color might be inspired from a Cumulonimbus Cloud.