Flying Island Cephalopod : LuftKraken
A fearsome combination of plant and animal, the LuftKraken starts out as a sort of seed, and eventually grows large enough for its float bladder to allow it to levitate. It also develops tentacles that allow it to free itself from the ground.
LuftKraken start out in life hovering slightly above ground, eating plant matter and developing in the warmth of the sun. As they get bigger, they begin feeding on animals, and the tree component's roots grow to become additional tentacles that help the LuftKraken feed.
After ten years growth, Luftkraken are big and fast enough to prey upon large animals, and their growth increases exponentially.
Eventually, their float bladders will increase in size, with the rest of the animal, to allow the LuftKraken to fly high into the atmosphere, where many of the larger ones remain, although some rare examples have had deformed Float Bladders, and therefore became immense near-ground dwellers.
LuftKraken always have heaps of earth to use as protection and a supply of nutrition for the photosynthesis-using tree part. It also serves as a nursery, as when the tree part dispenses its (Very Few) seeds that produce more LuftKraken, these will usually land in the safe, protected earth armor of the parent Luftkraken.
However, younger Luftkraken have neither sufficient control of their float bladders, or float bladders big enough to maintain their buoyancy, and will therefore go down to the level of others of their kind of a similar age.
Made Up Science