Terrabioforming is a compromise process that is partly terraforming (making a world habitable) and partly bioforming (changing ourselves to live in exotic environment). It is a sort of meet halfway process. While there are complex multicellular animals that are extremophiles, e.g. anaerobic loriciferans and hyperthermophilic (over 80 degrees Celsius) Pompeji worms, there is also the fact that intelligent brains consume much energy. For example, food scarcity would make most of the deep sea uninhabitable to intelligent genetically engineered (post)humans adapted to high pressure, total darkness and underwater breathing (though some would be able to live near the richest hydrothermal vents).