The Chimera was said to be one of the offspring of Typhon and Echidna and was capable of breathing fire. Sighting the beast served as an omen of disaster and peril, such as the eruption of volcanoes and the sinking of ships at sea. According to the legend of Bellerophon, the Chimera was slain when Bellerophon rode upon the Pegasus through the sky and felled the three-headed beast with a spear equipped with a lump of lead. The fiery breath of the Chimera melted the lead and it splashed against the beast, killing it.
In the modern era, the term "chimera" is used to describe a single organism that is composed of two or more different populations of genetically distinct cells that originated from different zygotes involved in sexual reproduction. If the different cells have emerged from the same zygote, the organism is called a mosaic. Chimeras are formed from at least four parent cells (two fertilized eggs or early embryos fused together). Each population of cells keeps its own character and the resulting organism is a mixture of tissues. Chimeras are typically seen in animals; there are some reports of human chimerism.