The monster known as the Chimera was one of the many offspring
of Typhon and Echidna. Therefore, the Chimera was a sibling
of the Nemean Lion, Cerberus, and many other unique animals.
It had the head and body of a lion, a goat head protruding
from its back, and its tail ended with a snakes head. From
all three of these terrible heads, it gushed fire.
The Chimera was ravaging the lands of Lycia until a young
hero named Bellerophon approached it atop the winged horse
Pegasus. Bellerophon had been sent by the King of Lycia to
kill the creature and shot arrows at it in an attempt to do
so. The Chimera spewed fire at the hero and flying steed,
but Bellerophon avoided the flames. When he realized that
his arrows were useless against the Chimera's flaming breath,
Bellerophon put a piece of lead on the tip of his spear and
shoved it down the Chimera's throat. The fiery breath of the
beast melted the lump of lead and killed it.
The word chimerism originated from this mythical creature
which is an exceedingly rare disorder where a life form carries
two different sets of DNA or has organs with DNA that doesn't
match the rest of the organism's body.