What are your troll headcanons?

Alright so, since no one has touched this forum I'll be the one inauguring it by asking you guys a question. What are your troll headcanons? as in anatomy, behavior, culture, among other things you've probably thought about? Is your character based in any of these?

I personally think that a troll's skin gets darker and darker with time. I have no real reason to believe this other than the fact that all of the ancestor's I've seen have had black as night skin. I thought it was played for drama before but then I saw Condy and was like "well, new headcanon now".

I have a couple troll headcannons, mostly about seadwellers. So in order to breathe underwater, they must have gills, which I imagine are on the sides of their necks and ribs. They inhale through their neck gills, and exhale through the gills on their ribs. And in order to not float to the surface all the time, they must have swim bladders as well.

The other headcannon is about fins- they have ear fins and I'd imagine they aren't the only fins, especially since I can't see much use in little fins on your head. So I think they have webbed toes, with the webbing being transparent sort of. I also think that as they get older, they develop a dorsal fin on their back- very long and thin, and flattens when they aren't underwater.

I saw this one headcannon that was 'seadwellers sleep with their eyes open' but I was like nooooope XD Especially since the accompanying drawing was Fef sleeping on the horn pile with her eyes wide open. Very creepy.

I have also some for the Seadwellers, Violets mostly... That is sort of opposed to what Esired posted but is my little personal headcanon-contribution thing ;w;

I see Violets more like cetaceans that fish creatures. I know there are some Purplebloods who had them as Lusii but PurpleBloods are still landwellers so it would me more likely for the Violets to still need to breath air but they are totally capable of living in water like dolphins and such. Also, some Violets are sort of chubby for that same reason, keeping themselves warm in cold waters, all depending on where they live.

That also remidns me, that being a "seadweller" is not just being on the sea, you can find Violets and some Tyrants living in pretty much any source of water, rivers, lakes, and so on.

i have some head cannon's from my tumblr trolls  
1) some sea dwellers  have gills located just behind their ear fins, leaving the neck relatively bare
2) some sea dwellers that are raised in a deep ocean environment, can develop a sort of bio illuminant reaction in there skin (glows in the dark)
3) sea dwellers can live for century's, so its not out of the question the an ancestor to still be alive somewhere when the troll is born/hatched  
4) a collar is a common mark for a slave, but sometimes a sign of affection or submission to a matesprit/kissmesis
will post more when i remember them

Money works similarly to the Wizzerding Money from the world of Harry Potter Gold>Silver>Copper coins.

Now my headcanon is that burgundy bloods have the warmest blood/body temperature of them all and it gets progressively colder the more up in the hemospectrum one is.

Minus rainbow drinkers. They are vampires, they are bound to be colder just because of the vampire factor.

thought of some more

1. going god tier, due to the healing effect of the resurrection after dyeing, the newly awakened god is completely clean of scar's and old wounds, much like when vriska regained her eye and arm after such a event.
this would also include body modifications like piercings and tattoos to be removed during the healing process

2. rainbow drinkers , it is thought that the fangs of a rainbow drinker contain a form of venom that deadens the victims nerves while preventing clots while feeding, this venom also lulls the victim in to a state of euphoria to prevent a struggle and possibly damage the fangs while lodged in the victim's flesh.
the dosage can also be consciously regulated by the rainbow drinker to suit the target, so a willing victim or lover/slave and receive a light dose to ease the pain and feel good about being food, and a unwilling or troublesome target can be drugged in to a instant coma if need be

a rainbow drinkers saliva can hold restorative properties, this works to heal the damage from their own fangs within their mouth and also to heal the marks left on their victim, either as a precaution to avoid suspicion, or as a courtesy and thank you to a willing meal