The Fly (1986)

Seth Brundle (Jeff Goldblum)is a research scientist, employed by Bartok Sciences, who has invented "Telepods"- two-matter transmission pods that teleport any object through space from one "Telepod" to the other "Telepod". But, it isn't until Seth meets journalist Veronica Quaife who inspires Seth to correct the system, that Seth achieves successful teleportation. But something goes horribly wrong when Seth uses himself as a guinea-pig in a matter transmission experiment, as he teleports himself, unaware his genes have been fused with a house fly that was trapped in the telepod with him. Seth now finds himself slowly transforming into a terrifying mutant creature known as "Brundlefly", fighting in a fierce battle as his mutated genes begins to take over.