Movie
Ruby Gillman, Teenage Kraken
Narrative tropes
Born Special
mediumRuby's powers derive entirely from bloodline — female family members transform upon ocean contact (inherited abilities); Grandmamah declares Ruby destined to inherit the kraken throne (chosen by fate/lineage); the source of Ruby's specialness is parentage and ancestry, not training or effort.
About this trope: Certain characters are inherently special by birth, blood, genetics, or prophecy — not through effort or choice. Greatness is innate, not earned.
You Can't Trust Anyone
mediumChelsea is revealed as Nerissa in disguise — a major trusted ally exposed as the primary antagonist (traitor hidden among allies); Ruby is manipulated into locating and retrieving the trident she then loses (protagonist discovers manipulation); the true enemy operated in plain sight within Ruby's inner circle (enemy hiding among allies).
About this trope: Trusted allies, institutions, or authority figures are secretly working against the protagonist. Paranoia is justified because betrayal is real and pervasive.
A Parent's Shadow
highAgatha's past decision to hide the trident and abandon the underwater kingdom is the inherited secret that drives the entire plot; Ruby is constantly defined against Grandmamah's legacy as Warrior Queen and Agatha's choices; Ruby must navigate between two predecessors' conflicting paths; the resolution has Ruby and the family redefining their identity on their own terms rather than fully conforming to either legacy.
About this trope: A character must grapple with the legacy of their parents or predecessors — living up to high standards, running from expectations, atoning for inherited sins, or forging their own path.
Cultural messages
Be Yourself
highRuby's family enforces strict concealment of their kraken nature (hiding abilities); Ruby is shy and awkward trying to pass as a normal teen (conformity as painful); her accidental underwater transformation is the reveal/self-acceptance pivot; she is ultimately celebrated as a hero by classmates (acceptance follows); and embracing her kraken powers is the direct source of her strength and victory.
About this message: A character hides or suppresses their true identity to conform, then finds strength and happiness by embracing who they really are. Authenticity is the real superpower.
Power Means Duty
mediumRuby possesses inherited kraken powers (extraordinary abilities); Grandmamah explicitly frames her destiny as protector of the ocean, making power an obligation (mentor frames duty); Ruby initially chafes against this path before accepting her role as defender in the climax (character struggles then accepts duty).
About this message: Those gifted with extraordinary abilities, wealth, or status have a moral obligation to use them for others — and the weight of that duty can be crushing. Privilege creates obligation.
Family Is Everything
highThe kraken family and its secrets are the central story engine; Ruby's growing distance from family during training is the key rupture; the climax is resolved specifically by Ruby, Agatha, and Grandmamah setting aside tensions and uniting (family bonds defeat the threat); the ending explicitly shows the family embracing their dual identity together (no-place-like-home resolution).
About this message: Family bonds — biological or found — are ultimately what saves the day, provides meaning, and matters most. Characters who stray from family suffer; those who return are rewarded.
Movies that share these tropes
Full plot (spoilers)
In the coastal town of Oceanside, Ruby Gillman is a shy, awkward teenage girl whose family secretly belongs to the kraken species. Her overprotective mother Agatha enforces a strict household rule: no contact with the ocean. When Ruby jumps into the water to rescue her crush Connor from drowning, she undergoes a dramatic transformation into a massive kraken, revealing her hidden nature to herself. Her parents explain that female members of their family transform into powerful Giant Krakens whenever they enter the ocean. Ruby's formidable grandmother, Grandmamah—the self-styled Warrior Queen of the Seven Seas—arrives and reveals that Ruby is destined to inherit the kraken throne and serve as protector of the ocean. Grandmamah explains that throughout history the krakens' greatest enemies have been mermaids, who are vain and power-hungry. The evil mermaid queen Nerissa once sought the all-powerful Trident of Oceanus, but Agatha defeated her and hid the trident before abandoning her underwater kingdom to live on land. A glamorous new student named Chelsea arrives at Ruby's high school and befriends her, encouraging Ruby to embrace her kraken powers and suggesting the two of them recover the trident together in order to end the kraken-mermaid conflict permanently. As Ruby trains her abilities under Grandmamah's guidance, she grows increasingly distant from her human friends. Eventually Ruby locates and retrieves the trident—only to be betrayed: Chelsea is Nerissa in disguise, and she seizes the trident for herself. Nerissa uses the trident to unleash an attack on Oceanside during prom night. Ruby, Agatha, and Grandmamah set aside their personal tensions and unite against Nerissa. Together they destroy the trident and defeat Nerissa. In the aftermath Ruby is celebrated as a hero by her classmates and finally gets to attend prom. The film ends with Ruby's family fully embracing their dual kraken-and-human identities.
Sources: Wikipedia, TMDb overview