Chimera -- a mythical monster with parts from various different animals: today, an organism with tissues of differing genetic composition.
Gigantes -- a race of giants who fought the Greek Olympaians: gigantic, obviously.
Hippocampus -- a Greek mythological creature with the front of a horse and the tail of a fish: today, the hippocampus is a region in the brain, so named because it is shaped like a hippocampus.
Hydra -- A Greek mythological water serpent with many heads which Hercules killed: clearly it comes from the root hydro-, water, as in hydrroelectric.
Python -- In Greek mythology, a dragon or serpent who guarded the oracle of Delphi until he was killed by Apollo: today, a kind of snake.
Ceres -- Roman goddess of agriculture: cereal.
Helios -- Greek sun god: heliocentric.
Eros -- Greek god of love: erotic.
Hypnos -- Greek god of sleep: hypnotize
Typhoon is a word with an interesting history, influenced to an extent by a creature of Greek mythology. The Online Etymology Dictionary has this to say:
the modern word represents a coincidence and convergence of at least two unrelated words of similar sound and sense. Tiphon "violent storm, whirlwind, tornado" is recorded from 1555, from Gk. typhon "whirlwind," personified as a giant, father of the winds, perhaps from typhein "to smoke." The meaning "cyclone, violent hurricane of India or the China Seas" (1588) is first recorded in T. Hickock's translation of an account in Italian of a voyage to the East Indies by Cæsar Frederick, a merchant of Venice, probably borrowed from, or infl. by, Chinese (Cantonese) tai fung "a great wind," from tu "big" + feng "wind;" name given to violent cyclonic storms in the China seas. A third possibility is tufan, a word in Arabic, Persian and Hindi meaning "big cyclonic storm" (and the source of Port. tufao), which may be from Gk. typhon but commonly is said to be a noun of action from Arabic tafa "to turn round."