Toxic

If you think the only people who care about metaphorical-to-literal transcendence are pedantic linguists like yours truly, then you are mistaken.

It is important to be aware that metaphors are woven to the very fabric of language itself, and affect its dynamism.

Take toxin, a relatively modern concept due to the advance in medicine. If you trace the etymology, it comes from Ancient Greek word toxikos (τοξικός), which "[pertains] to arrows or archery". The concept of toxin being deadly and fast-acting is then borrowed from arrows: toxin is a metaphor.

Consider how toxin now has transcended its metaphorical husk, flapping wings, gliding gracefully on the literal plane, landing on the minds unaware that it is a denizen of the otherworld.