Fire Dragon
A variant of Acropora coral (Acropora sp.)

Photo: The original uploader was Elapied at French Wikipedia . · CC BY-SA 2.0 fr
Representative Acropora coral image. A confirmed image of this exact morph isn't available yet.
A bright orange form of Acropora carduus, a deep-water species with an unusual growth habit. It copes with lower light than most Acropora, and its seller warns against dipping it.
Other SPS Corals variants
Staghorn / Table Acropora (growth forms)Green Slimer (Acropora yongei)Tricolor / Tricolor Valida (Acropora valida)Pink/Purple Stylophora-tip 'Strawberry Shortcake' (Acropora microclados)Walt Disney (Acropora tenuis)Strawberry Shortcake (SSC) AcroporaOregon Tort (Oregon Blue Tortuosa)Rainbow TenuisRed Dragon AcroporaPink Lemonade AcroporaCali Tort (California Blue Tortuosa)Tierra del Fuego (TDF) AcroporaPikachu AcroporaJason Fox Homewrecker / Miyagi TortPink Cadillac AcroporaWalt DisneyStrawberry ShortcakeWWC Red ShortcakeOregon TortJason Fox HomewreckerTyree Pink LemonadeJackson's Rainbow TenuisRed PlanetMiyagi TortHawkins EchinataGARF BonsaiORA PearlberryCotton Candy TenuisVivid's Bali ShortcakeJF Fox FlameCC Pink Highlighter TenuisMiami OrchidPlum CrazyBlue IrisEthereal AcroGreen PlanetGreen VelvetIce TortLaura's Purple PolypYellow Tip StagPhil's GranulosaPurple NanaPurple PlasmaRose MilleporaStuber StagSolitaryensisLavender StagJoe the CoralFrogskinBlue VoodooBorealisRoscoe's BluePurple MonsterSunset MilleporaSapphire MilleporaSuper Blue TenuisPonape RainbowToxic Green FloridaRainbow SpliceFruity SpliceRaspberry SpliceBubbleyumForbidden Fruit SpeciosaRocky BalboaCherry BombMai TaiConfetti AcroporaDoctor ManhattanKermit the FrogGlow StickPC Rainbow