Acid and Cyanide are a pair of venomous, magical snakes serving under Grootslang and are the primary antagonists of Season 5. They're also the ones responsable for Flooding Beach City and destroying the Water Tower.
Physical Appearance
Both Acid and Cyanide are five foot long vipers, resembling an adder. While looking alike, Acid is darker in color compared to Cyanide, and has diamonds running down her back in contrast to Cyanide's two lines.
Personality
Both snakes are rather sly, calculative, and manipulative upon others. Both snakes enjoy manipulating others out of their comfort zones and casting doubt on their lives, driving them to do more michevious activities.
It is difficult to really say on who's in charge, yet it seemed that they share their role equally amongst eachother with little bickering over what to do.
History
Season 5
Cluster Arc
Acid and Cyanide wake up at the beginning of spring, seemingly after a winter hibernation, and hearing news about The Cluster. Both snakes agreed that this would be a proper distraction for the Crystal Gems and Mane Six as they got the greenlight to go into Beach City and cause some chaos amongst the townsfolk.
Their first act upon the town is going to Peedee Fryman, and ordering something "off-menu", which subsequently triggered a rivalry to form between Mr. Fryman and Kofi Pizza, restarting the Restaurant Wars. On seeing this, both snakes couldn't help but snicker at a job well done. Their next act was directly aimed to Sadie Miller, Acid specifically going in and corrupting her mind by making her go into thievery in order to find something she can enjoy without her mother pestering her over it. Their attack on the Crystal Gems came when they left a Gem Mask at the Crystal Temple, which they used on Pearl to make her sabotage the Gem Drill project, despite it threatening the entire planet.
They show up once hearing word of Amethyst and Steven Universe's upcoming duel, mocking them and calling the concept simply stupid, but decide to check out the duel anyway. They plan to bite one of the combatants during the fight, but didn't manage to attack them, as they nearly got caught by Yellow Diamond. They left Homeworld, and decide to talk to Amethyst directly, mocking her. However, their mockery had the opposite effect and actually helped Amethyst out in trying to prove herself. The two went off to Equus before The Cluster became alive.
Serpent Arc
The snakes notice that Applejack, Rainbow Dash, Ronaldo Fryman, Peedee Fryman, Kiki Pizza, and Jenny Pizza want to stop the Restaurant Wars, and both snakes decide to sabotage their attempts. This included tripping Ronaldo during the first act and making it appear like he was attacking Jenny, disguising as Jane (Ronaldo's girlfriend) during the second attempt in a "Romeo and Juliet" act, and spoiling the food at the third attempt in trying to open another restaurant. It was their third act though that got them caught, and AJ and Rainbow caught them on their final attempt so they wouldn't interfere, yet both snakes managed to escape. Acid and Cyanide appear with Grootslang sometime later to confront Lars Barriga, wrecking his treat for Buck Dewey's potluck, and during the Autumn Country Drive, Acid found Amethyst and got her to thinking that Connie Maheswaran was stealing Steven away from her.
Their biggest involvement was sending a signal out to Beach City in the form of a United Emergency Signal (UES), warning of an oncoming Hurricane coming to destroy the town, just so the residents leave the town and for the Gems to lock themselves away. Once that was done, the snakes went to the Beach City Water Tower, breaking the legs, and making it collapse onto the U Store. This resulted in the Beach City Flooding. They slip away after the group over in Griffinstone, and managing to paralyze Connie and Amethyst, tossing them down the nearby clifface. Both snakes were soon found by the others, along with Gilda, but they got them off their backs by warning them of those stuck down on the cliff, letting them slip away.
Their next involvement came from a more petty crime in Ponyville, cutting off Rarity's mane during the night. After that, they went over to see Spike during their meeting, about to convince him to eat the other Gems, when Rarity came in and exposed them to everyone. They were taken by Yellow Diamond, and electrocuted into revealing Grootslang's location, being left behind with White Diamond to their fate. The two somehow reappear with Grootslang, waiting for the others to arrive with their bounty, but in the end they end up trapped within Grootslang's Hat.
Abilities
Magical venom
Their venom is different from standard vipers, and have varying effects. Cyanide's, for example, is able to actually spoil food to the point when it's inedible, while Acid's venom can melt away metal. Both of their venom though still holds paralysis, and can make those bitten unable to move.
Transformation
While unclear if both snakes could do this, but one of them is able to disguise herself as a human being in order to deceive.
Trivia
- Acid and Cyanide are one of the few characters to break the fourth wall. Unlike any of the others, they actually use it to insult the audience, saying they can't do anything about the Beach City Flooding.