|“He used Fang Kwon Do!”|
|— Rattla after Skales did a standing kick to Slithraa in the Slither Pit.|
Rattla is the Scout for the Hypnobrai tribe. He has a dark blue face with red eyes, with the left eye being slightly larger than the right. The rest of his body is mostly light grey, save the dark blue markings on his front and his dark gray hands. He also has a small cobra-like hood on the back of his head.
Rattla is not a particularly strong Hypnobrai, having a limited hypnosis ability. He attempts to hone his skills on ice bugs, but their lack of eyes makes this tactic rather ineffective.
Rattla likes to practice his limited hypnotic skills on ice bugs he finds in the caves. It’s often hard, as most ice bugs have no eyes. He has recently started experimenting with singing or talking them to sleep with boring recounts of fights he’s never actually been in, before he eats them. He has had slim to no results so far.
NOTE: In the cartoon, the Serpentine ranks feature multiple identical instances of several characters. As such, appearances of "Rattla" refer to any notable situations featuring a Hypnobrai Scout, and to any group instances where Rattla himself would logically have to appear.
Several scouts were among the Hypnobrai ranks when Lloyd Garmadon opened the Hypnobrai Tomb and (accidentally) gained the allegiance of General Slithraa. The scouts joined the raid on Jamanakai Village, hypnotizing the villagers and stealing their candy. When the Ninja arrived, the scouts and their comrades fought furiously, but retreated after the Ninja stole Slithraa's staff and used it to cure the hypnotized villagers.
The Hypnobrai were later put to work in Wildwood Forest, building a treehouse fortress for Lloyd. During the fort's construction, a Hypnobrai Scout was briefly called away by Skales, who revealed that he had hypnotized Cole and was using him to spy on the Ninja in their monastery. The Scout expressed amazement at Skales' cunning, but quickly went back to work when Slithraa found his subordinates slacking off.
The next day, the fortress came under attack by the Ninja, who had been led to the structure by a strange bird. As the Ninja began cutting the ropes holding the fortress up, Skales betrayed Lloyd and took him prisoner, with a few nearby Scouts laughing as their would-be master fell into one of his own fort's boobytraps. With the brainwashed Cole distracting his comrades, Skales led the Hypnobrai to the Monastery of Spinjitzu, where they reclaimed their staff and burned the building to the ground.
Rattla and his fellow Hypnobrai returned to their tomb, where Slithraa ordered Skales to return his staff. However, Skales refused to obey, prompting the other Hypnobrai to eagerly anticipate a Slither Pit. Moments later, their hopes were confirmed, as Skales formally challenged Slithraa to a battle over the staff—and thus, leadership of the Hypnobrai.
Scouts and Soldiers alike gathered around the Slither Pit arena as the match began. Eventually, Skales gained the upper hand by mesmerizing Slithraa with his body movements and delivering a fierce kick to his General's chin, a move that Rattla identified as "Fang Kwon Do." In the end, Skales triumphed over Slithraa, and Rattla joined the other Hypnobrai in cheering the name of their new General. This forced Lloyd to leave the Hypnobrai tomb.
The Hypnobrai spot another tribe of Serpentine and proceed to battle. They soon realize it was the Fangpyre, a tribe whose general, Fangtom, is a close friend of Skales. Mezmo soon corners Lloyd with other Hypnobrai and Fangpyre but the would-be evil lord escaped when he was catapulted away by the Rattlecopter.
Rattla, as well as many other Hypnobrai, are present for Pythor's failed attempt to unite the tribes. They soon pursue the four Ninja, only to slip and fall in the icy tunnel.
Rattla watches the Slither Pit fight between the Generals. When a Serpentine dropped his maracas, it is revealed he is Lloyd. The Serpentine captured him and placed him in a cage.
Later, they watched the Ninja fight the mysterious Samurai X.
Rattla is present at the Serpentine underground fortress. He witnesses Pythor discover the riddle to where the map of the four silver Fangblades were.
Rattla is there at the Mega Monster Amusement Park where Pythor unearths the Hypnobrai Fangblade. He later catches up and uncovers the Samurai and leaves the amusement park.
A Hypnobrai Scout joined Skales and two Soldiers in watching the annual "Ninjago Talent" show in "disguise" (fake beards strapped to their chins). He applauded the Treble Makers' act and booed the Ninja when they came on the stage. When it seemed that the Ninja's act was going to be a hit, Skales sent his forces to hinder them, but their efforts only enhanced the Ninja's performance. The Serpentine were forced to retreat, but not before Pythor secured the Blade Cup (and the Fangblade within) while distracting the Ninja with an attack on Cole's father.
The Serpentine successfully found the Fangblade in the Fire Temple. When Pythor saw the Ninja coming for them, he ordered the Serpentine to attack. They managed to destabilize the volcano more and trap the Ninja inside.
After fighting the Ninja, the Serpentine disarmed the Ninja and put them in a Vengestone cage. They celebrated by having a Slither Pit, but eventually had to fight Garmadon and the Skulkin.
The Serpentine helped clear a bus of its passengers so they could turn it into the Serpentine Train. The Ninja eventually attacked them, but Pythor was the only Serpentine to make it to the City of Ouroboros.
After realizing the Devourer is destroying Ninjago, the Serpentine took refuge in the Fangpyre Tomb.
Rattla was one of the many Serpentine watching Skales try to take control the Serpentine. When Garmadon took control instead and threatened them, he agreed to go with him inside the Black Bounty.
After reaching the Golden Peaks, Rattla cheered after Garmadon successfully made the Mega Weapon.
During the Black Bounty's pursuit of the Ultra Dragon, one of the Hypnobrai scouts stood by Garmadon on the deck, eager to see the Mega Weapon in action. However when the dark lord was unable to unlock the weapons power, the scout began to laugh along with the other Serpentine present.
Later when Garmadon inadvertently brought Captain Soto's crew back to life, a Hypnobrai scout was among those of the main deck who claimed the Bounty to be there ship, though was imprisoned in the brig by the pirates.
During the third leg of the annual Ninjaball Run, Rattla joined several other Serpentine in attacking the Ninja while they tried to refuel their Ultra Sonic Raider with fuel from Ed and Edna's jalopy. Rattla landed on top of the Raider, where he faced off with Zane. His attempt to hypnotize the Nindroid failed when Zane turned his head 180 degrees to avoid meeting Rattla's gaze.
While Rattla recoiled in shock and disgust, Kai and Cole threw snowballs at his face, leaving him temporarily blinded. Zane used the opportunity to knock the Hypnobrai Scout off of the Raider—unfortunately, Rattla landed in Ed and Edna's jalopy, causing them to swerve into the Raider and begin what would become a massive pile-up involving most of the remaining contestants.
The Serpentine watch a Slither Pit fight, but Garmadon interrupted them.
At the City of Ouroboros, the Serpentine cheer Skales as he is being crowned as the Serpentine King. When they found the Stone Army Tomb, they witnessed the Devourer's venom reviving them. They tried to fight and escape, but was trapped inside.
The Hatching (Flashback)
Wu told the Ninja about the Time Twins, starting with the Serpentine War and how the Serpentine attacked Ninjago.
- His name is a pun of the word "rattle."
- He is the only serpentine to have crossed eyes.
- Rattla serves as an enemy in various levels of LEGO Ninjago: Wu-Cru.
- He is one of the only serpentine to appear in Ninjago: Nindroids, alongside Snike.