AGH! SNEK! A SNEK! AWOOOOO IT'S A SNEEEEEEK!
This is the thrai, most dangerous danger noodle in Tsyllaes, and its shape is therefore based off an eastern brown snake because it's always bugged me that the deadliest snake in the world (depending on your metric) is just… brown… so Tsyllaes gets one that's goooooooold with six brown bands around its neck.
They're deadly because of just about every factor. They like to hide out the heat of the day in places where people are likely to find them (like poor iccle Ruyn's toy box) and, while they're more likely to quietly piss off if they're disturbed, they're definitely the snake most likely to rear up, like that one up there, and bite just so they can get away. They're not stupid, they know they can't actually take on a creature as large as a human, but they know they can hold off the human long enough to escape.
Their bite, of course, is just the worst. One bite causes the victim's throat to close over so they start choking while their blood very quickly starts turning to stringy clotted jelly. The site of the wound swells and turns red while the rest of the skin blotches with red, purple and yellow and the eyes cloud over with yellow. The victim is unconscious within a few minutes and dead in twenty.
Thrais occupy a special place in Raykinian culture, something to be respected, a reminder of how deadly Aeia's desert can be, even in the city, and you have to be constantly vigilant living in her land. She leaves you under no illusions as to whose world this is. The Golden Thrai, Ni-Yana's richest pub, is named after it because its booze is Potent and Deadly.