Nuclear Green
A variant of Zoanthids (Zoanthus sp.)

Illustration, not a photograph of a real specimen. Individuals vary.
A Palythoa with an intensely bright, glowing green face. A classic, very fast-spreading 'green paly' staple in the hobby.
Backstory
A ubiquitous Palythoa sold by Tidal Gardens (as 'Nuclear Green Palythoas') and essentially every coral vendor. One of the most common named palys and a frequent beginner coral; original lineage is debated and largely irrelevant given how widely propagated it is.
Keeper tips for this variant
Extremely hardy; place anywhere from sand bed to mid rock under moderate light. It spreads aggressively, so keep it away from slower neighbors.
Other Zoanthids variants
Eagle EyeRastaBrown/wild button polypsBlue HornetRainbow IncineratorPeople EaterUtter ChaosFruit LoopsSunny DWWC BowsersArmageddonGorilla NippleDaisy CutterTubbs BlueMagicianGobstopperBlow PopPink ZipperKrakatoaSpeckled KrakatoaGrand Master Krakatoa (GMK)Whammin WatermelonBam BamDaisy DukeKing MidasMy ClementineGoblins on FirePink DiamondsLunar EclipseArmor of GodBob MarleyPandoraWildflowerRainbow HornetJF BloodshotEye of RaGreat Owl ZoaPunk RockerPurple HornetBlueberry FieldsStratosphereQueen StratSupermanKryptonitePlayboy BunnyDarth MaulSakuraGreen Bay PackersBlue AgaveChucky's BrideGod of WarBlack Hole SunBlue SteelCat's EyeCreamsicleEye of SauronIncredible HulkFrozen ArmageddonNebulaAngel WingsStarscreamSun EaterJungle JuiceMandarinSolar FlareKung Fu FighterDeath StarNirvanaMean GreenScrambled EggsRed HornetStrawberry WineMiami ViceMary JaneTaserPink KrakatoaBlue Eyed BlondesAOICandy Apple RedAlien AntivenomGatoradeOompa LoompaSweet ToothOrange OxideSonic FlareSpace ChaosWhite ZombieBloodsuckerKedd's RedsMohawkCandy CrushFairy MuncherUltimate FireToxic RainTequila SunrisePurple HeartOrange Dragon EyeMambo JamboPumpkin SeedsLittle Shop of HorrorsYellow SubmarineFrozen NebulaCharmanderBlue Boo BerryVampireSour PunchPacmanFake ChiliNightmareRasta CousinsOrange RainbowSpellbinderGod BeastPredatorFrozen HornetTiger HornetJawbreaker HornetMurder HornetAcid RainSuperstarZombie EyeInsane RainbowPunch DrunkSafecrackerMystiqueBansheePrometheanTwizzlersAphroditeLaffy TaffyEmeralds on FireAtmosphereAntimatterLA LakersTutti FruttiAwesome BlossomBlack BellaExosphereSnowglobeSuper SaiyanGold MaulHalle BerryKoala EyesFruitopiaPerennial DanceOmegaRing of Fire