"Takua held on as the Toa climbed steadily upward, one sword's length at a time, trying to calm the wild, terrified beating of his heart." 
Onua and Whenua once shared a meal from their packs.
"Now he floundered, hand to his throat as the liquid protodermis filled his mouth and lungs."
When the Toa Metru encountered Morbuzakh seeds, they seemed to be already familiar with the concept of plants using seeds to reproduce.
Nuju once intentionally took a deep breath to expand his chest to allow himself to escape vines from Morbuzakh seeds when he let the breath out.
When Turaga Lhikan died, his eyes went dark, and his heartlight ceased to flash.
Virtually everything in the BIONICLE universe – Piraka, Toa, Matoran, Rahi beasts – was biomechanical. This meant that it was a combination of muscles, organs, and mechanical parts. Most BIONICLE characters were not robots, but living, thinking beings who just happened to have machine parts and armor. For example, Piraka could plan and scheme and feel emotions like anger and happiness. They needed to breathe, sleep, and consume nutrition to keep energized. They had muscles that helped them run, jump, and fight, lungs that took in air, eyes that saw, and wicked smiles. They were neither completely organic nor completely robotic, but a combination of living being and machine. The benefits of this included the fact that their machine parts and armor made them much less vulnerable to injury. If they were injured, they could repair themselves much easier than a human being. BIONICLE beings consisted of mechanical parts connected by muscle, so if the needed to rebuild themselves, they could simply attach another part to their bodies. The muscle grew to connect it, and then it was ready to use. The result of this was powerful beings who were very hard to hurt, had extremely long lifespans, and who could even upgrade themselves as long as they had the technology to help them do it. Matoran, for example, were known to live for thousands of years and completely rebuilt themselves at least once in the BIONICLE story.
Nektann once spat on the ground.
Vezon once claimed he liked collecting seashells and leaves, indicating that these things existed in the Matoran universe.
Any self-respecting Nynrah crafter would be capable of building a new mechanical part to replace a damaged limb.
Toa, Matoran, and originally the Makuta were bio-mechanical, a combination of organic tissue and mechanical parts.
Daxia had a central well of energy for when Order of Mata Nui members got hungry.
There was no way to force a spirit out of a body or to force antidermis out of undamaged armor.
If a spirit left a body and the body went uninhabited for a certain amount of time, the body died.
Biomechanical beings did not have blood, more likely some kind of lubricating fluid. They had some organic organs (it was never specified which ones). Matoran did not have blood as such; what they had was more of a lubrication system.
Romantic love did not exist among the biomechanical beings in the Matoran universe. It did however exist on Bara Magna.
Mind control powers would work on other inhabitants of the Matoran universe, but not on natives of Spherus Magna.
Matoran were capable of drawing energy from fish and other foods through touch. Rahi were likewise able to draw energy from other Rahi. When Skakdi ate through their mouths, anything they consumed would be destroyed by the energies inside them, so there was no waste product. They did not need a digestive system to absorb energy because they did that as soon as they made physical contact, as Matoran could.
Matoran did not have teeth, as they did not need to chew anything.
Matoran did sleep, although they did not sleep as much as an Agori would. If a Matoran was exhausted or tired, he could restore energy through a recharge, but sleep was better and more efficient.
There was no biological reproduction in the Matoran universe; it was all done by machine. This technology could evolve over time, as what works in theory often does not work in practice and needs to be improved upon.
The Makuta were able to create plant species that could reproduce using seeds. Although they also could have created Rahi capable of reproduction, they never did so.
Fully robotic creatures such as Bohrok, Vahki, and Maxilos were fully mechanical and did not have organic protodermis parts.
There was no romantic love in the Matoran universe. Because its society had no need for mating, reproduction, or marriage in order to function, there was no reason for it to ever develop.
Biologically, the class of animal that Matoran were most similar to was mammals.
A Matoran who was starving probably would have had difficulty managing basic processes, the same way a machine would run down without power.
The presence of teeth on species like Botar's species and Vortixx did not necessarily mean that they used them for eating – teeth could also be used for offense and defense, not just eating.
Plants were made from organic protodermis.
Matoran did not reproduce biologically.
Matoran could get hurt, sick, or injured, since they were partly organic.
No new Matoran, Rahi, etc. came into being during their time living on the island of Mata Nui.
Matoran "ate" by absorbing energy directly from things, not consuming them, and did not taste it.
A combined being's voice would probably depend on its component beings.
Beings would probably have to be the same species to combine.
Masks were similar to batteries; this was seen when the Toa Mata first put their masks on after arriving on the island of Mata Nui. Biomechanical beings weren't mostly dependent on organic tissue. Their mechanical components potentially made their organic components more efficient. Their lungs and muscle tissue were organic; their muscle tissue connected mechanical parts. It is possible for muscle tissue to detach and regrow, as evidenced when the Toa Mata reassembled themselves and when the Mata Nui Matoran rebuilt themselves.
When Rahi ate a being, they likely left behind a lifeless carcass after absorbing energy from it.
On Metru Nui, Ga-Metru had a location that Matoran had to travel to once a year to recharge their energy.
Armor allowed for the attachment of items such as backpacks. These were attached similarly to how Kanohi are worn.
If a Matoran rebuilt him or herself powerful mechanical parts, he or she would need the necessary muscle tissue to support them. Adding a Bohrok shield wouldn't accomplish anything because the Matoran wouldn't have the elemental energy necessary to power it.
When the organic tissue of a deceased Matoran rotted or was removed, the corpse could be used as raw materials. This would likely be considered desecration.
Rahi were capable of absorbing energy like Matoran, but were not aware of this. They chewed their food. If swallowed, their systems would likely be efficient enough to produce no waste.
The Piraka were capable of removing the Toa Nuva's armor.
Armor was removable.
Masks got their color from being worn, but armor and other items were likely dyed.
Matoran consisted of mechanical parts linked together by organic tissue, but there was no organic tissue within their mechanical parts. They were able to disconnect their organic tissue without suffering, and the tissue would fuse to a new mechanical part when added.
A Matoran body would be incapable of containing the energies of a Toa. That would require the greater size and muscle mass of a Toa body.
It is implied that an unattended corpse would leave behind no evidence if revisited 1000 years later.
Gender was not determined by a being's personality. The being's personality was one of the only major differences one could observe in the genders because the genders did not have physical differences.
A Toa would be capable of taking themselves apart.
Being biomechanical, Matoran had sensory apparatuses so they could smell, hear, and experience other sensations without obvious noses or ears.
It was very unlikely that Matoran could cry tears.
Matoran could likely cough, as they had lungs.
Matoran had no need to taste because it wasn't important given how they ate.
Matoran joints didn't need external lubrication.
Matoran were incapable of blushing.
Matoran were mechanical parts connected by organic tissue. Given that they had no skin, they had no sweat glands and did not produce sweat.
Matoran were unlikely to have spit.
Not every fusion would lose its sanity over time, but it would be an unsettling experience.
If a Matoran broke a limb, it would be possible to cast him or her a new one or to somehow repair it.
Lifespans could reach 100,000 years.
Aging is not really an issue for Matoran because they could live thousands or potentially even hundreds of thousands of years.
When the Shadowed One was aged by Voporak, his appearance did not noticeably change.
The Shadowed One's strength most likely diminished when he was aged.
The Shadowed One was just as powerful after he was aged as he was prior.
The Shadowed One's reduced lifespan after his encounter with Voporak was not a big issue for him because of the extremely long lifespans of biomechanical beings.
Matoran lived easily tens of thousands of years on average.
Matoran could die of old age.
Inhabitants were not made of protodermis.
Unlike the Matoran universe, the concept of romance existed on Spherus Magna.
The inhabitants of Spherus Magna actually ingested food.
Agori and Glatorian had the same life spans as Matoran and Toa. Not all inhabitants of Bara Magna had this same life span.
Inhabitants of Spherus Magna could not tap into inner light or shadow.
The helmets the Glatorian, Vorox, and others on Bara Magna wore dated back thousands and thousands of years.
Inhabitants of Spherus Magna were not born with their mechanical implants, and they could live just as well without them.
Agori had children and were made up of cells like normal living animals. They were born fully organic and chose later in life to have mechanical parts implanted which could outperform the organic.
Agori and Glatorian did not require their mechanical implants to live. It is unknown what their natural lifespan without mechanical implants was.
Agori and Glatorian were most likely genetically related.
Agori and Glatorian cannot interbreed.
Although Greg understood the need for changing the design of the characters for the movies, he was not particularly invested in the "look" either way and had no opinion about it.
Toa and Vahki didn't have hands in set form, but they did in the books.
In BIONICLE 3: Web of Shadows, the Toa Hordika only have one tool each. This was done for the purposes of their animation, but they canonically had two tools, as depicted in the comics, books, and sets. The sets are the official look of the characters.
Most physical differences between Toa, such as height, were set differences and not story differences.
The Toa Mata were not shorter than the Toa Metru in the story.
Greg Farshtey imagined Matoran speaking without mouthpieces on their masks, but the moviemakers needed to go in a different direction.
Matoran head shapes didn't change between 2004 and 2001.