H. giganteus may refer to: Hagryphus giganteus, an oviraptorosaurian theropod dinosaur species from the Upper Cretaceous Period of what is now Utah Helianthus giganteus, the giant sunflower or tall sunflower, a plant species native to the eastern United States Hemidactylus giganteus, the giant leaf-toed gecko, a lizard species found in India Herpetosiphon giganteus, a bacterium species Hirundapus giganteus, the brown-backed needletail, a large swift species