Windwhales

From Glen Cook Wiki

Windwhales are enormous flying creatures which live in the Plain of Fear. They can reach sizes exceeding five hundred yards long and seventy to a hundred yards wide. They resemble a cross between a zeppelin and a jellyfish, with dangling tentacles that they use to gather food. Their buoyancy is partially provided by enormous internal sacs of a flammable gas, possibly hydrogen. They are not originally native to this world, but come from another dimension/plane of existence; like the other odd extraplanar denizens of the Plain, windwhales were brought over in ages past by the god Old Father Tree. Windwhales live in a kind of symbiotic relationship with large flying manta creatures which nest on the whales' backs. Windwhales seem to be somewhat intelligent, and are capable of taking direction from the Tree. They smell terrible.

They can fly as high as a few miles; however windwhales feed by hovering low over the ground and ripping everything up in their path with their enormous tentacles, reportedly capable of snapping a 500-year old oak tree in two. Any one of them is easily capable of completely demolishing a good-sized town. Normally they remain in the confines of the Plain of Fear, but under the direction of the White Rose and at Old Father Tree's orders, they sail beyond these limits for a series of military operations. They prove somewhat vulnerable to concerted military defenses (especially involving major magic) but are nonetheless the biggest weapon in Darling's arsenal.

Windwhales play crucial roles in the destruction of the Dominator and the Limper, beings too powerful to be physically restrained by any other creature.