The Hypnobrai are a tribe of Serpentine, based on the speckled cobra with a hint of rattlesnake as well. They have the ability to hypnotize people at will, thus making their tribe name a pun on the word "hypnotize."
- All Hypnobrai have a cobra-like hood, with Soldiers, Warriors, and Generals having a full cobra head.
- The head mold of their Scouts and Soldiers are the same as the ones of the Venomari.
- Their colors are generally blue, yellow, and light/medium gray.
- Their eyes are red, with concentric circle patterns resembling a large spiral; these patterns rotate whenever the Hypnobrai begin hypnotizing their opponent(s).
The Hypnobrai have the power of hypnotism. They rattle their tails and stare at the victim, and if the victim happens to look their way, they are placed under their control. This is usually a direct enslavement, but the Hypnobrai can also plant post-hypnotic commands, turning the victim into a sleeper agent as Skales did with Cole. In this state, the Hypnobrai can see through their victim's eyes, and enforce their hypnotic control at any time.
The Hypnobrai Staff has anti-venom that will undo the hypnotic spell. They have a protective second eyelid over their eyes, for when they are not hypnotizing someone.
The Hypnobrai's hypnotic stare only works if they can make eye contact with a victim for a certain period of time. As such, avoiding eye contact will prevent one from becoming hypnotized, but the difficulty of fighting blind can be a hindrance. In "All of Nothing," Kai trained himself to fight with his eyes closed in order to avoid losing his advantage over the Hypnobrai, while in "Ninjaball Run," Zane simply turned his head around to avoid being hypnotized by Rattla.
Another way to avoid the Hypnobrai's gaze is to attack them or otherwise break their concentration, as Skales did during his battle against Slithraa in the Slither Pit in "Home." However, the Hypnobrai can still induce partial hypnosis in their victims if interrupted, as seen when Skales attempted to hypnotize Cole in "Rise of the Snakes;" although the hypnosis was interrupted, Skales was still able to see through Cole's eyes at will and actively command him to attack the other Ninja when they attacked Lloyd's new treehouse base.
The most beneficial means of circumventing Hypnobrai hypnotism is to use a reflective surface to bounce their gaze back at them—not only does this negate their attempt to hypnotize their victim, but it also leaves them suggestible to commands. Lloyd Garmadon inadvertently discovered this weakness when Slithraa accidentally reflected his hypnotic gaze onto himself with the surface of an icicle, allowing Lloyd to gain control of the Hypnobrai through their brainwashed general.
- The Hypnobrai were the first snake tribe to appear in Ninjago: Masters of Spinjitzu. It is also the first and, so far, only tribe to have seen a revolt, or a Slither Pit duel to determine a new General.
- Their name is derived from the word "Hypnosis," due to it being their main trait. It may also stem from cobra, which they resemble, such that the name comes from Hypnobra plus the suffix -ai.
- The Hypnobrai have the lowest number of Warriors seen in the series—they never appear to have more than one at any given time, and Slithraa disappears from the series after "The Snake King," leaving the Hypnobrai ranks to be filled entirely by Soldiers and Scouts.
- When they rattle their tail and tilt their head, that warns people that they will be put in a hypnotic trance, thus they will be able to avoid their glare.
- Chen's staff appears to have a Hypnobrai tail.
- The Character Trailer for the Hypnobrai misspells them as the "Hybnobrai."
- It appears that the higher the rank within the Hypnobrai tribe, the darker the blue coloring a Serpentine has.