The Fly (1986)

In the superior and scary remake by master of horror David Cronenberg - about a scientist who had accidentally merged himself at a molecular-genetic level with an ordinary housefly during a teleportation incident using an experimental telepod device:

• the gruesome scene when a baboon was teleported inside out during an experiment gone awry - the squirming remains were viewed
• the scene of girlfriend/lover/science reporter Veronica Quaife (Geena Davis) feeling hairs growing on the back of a slowly-degenerating Seth Brundle (Jeff Goldblum), her shy scientist boyfriend
• Seth's first realization that he had become fused with a fly - the computer typed out: "FUSION OF BRUNDLE AND FLY AT MOLECULAR-GENETIC LEVEL" - his new name was Brundlefly
• his displays of superhuman strength after a teleport session - breaking a competitor's arm during an arm-wrestling match in a bar (with the bone protruding) - and then climbing up and down walls, etc.
• a degenerating Seth's ear falling off in front of his girlfriend/lover/science reporter Veronica Quaife (Geena Davis), as he clutched her in fear and whispered: "I'm scared. Help me. Please"
• Seth's videotaped explanation of vomiting during preparations for his breakfast
• the scene in which Veronica experienced a nightmare of aborting a maggot
• the scene in front of his bathroom mirror when slowly-degenerating and mutating Seth stored "relics" of his human body in the cabinet ("the Brundle Museum of Natural History")

The Rapid Disintegration of Seth Into a Fly Creature

• his warning to Veronica in his 'insect politics' speech to leave and never come back because he might hurt her: ("You have to leave now, and never come back here. Have you ever heard of insect politics? Neither have I. Insects don't have politics. They're very brutal. No compassion, no compromise. We can't trust the insect. I'd like to become the first insect politician. You see, I'd like to, but, oh, I'm afraid, uh... I'm saying, I'm saying, I-I'm an insect who dreamt he was a man but he loved it. But now the dream is over and the insect is awake....I'm saying: 'I'll hurt you if you stay.'")
• the scene of Seth's painful attack on Stathis Borans (John Getz) by using acidic digestive vomit; Seth first covered his left fist with the white substance, causing it to disintegrate into a bloody stump. He then regurgitated the whitish acid onto his right ankle and peeled off his foot. At Veronica's urging and begging, he paused
• the scene of Seth's horrifying discussion with Veronica, pleading with her: "Help me. Help me to be human"; he asked her to engage in a fusion sequence (with a two minute countdown) to come together with him: "I go there. You go there. We come apart. And then we come together there. You, me, and the baby, together...it will be the ultimate family, a family of three joined together in one body, more human than I am alone"; as she resisted his attempt to drag and throw her into the transporter, his fleshy skin from his jaw fell off in her hand and he was transformed, in the most grotesque scene of all, into an actual human fly; his plan failed when he was inadvertently fused with metallic components of his telepod device; the seriously-wounded Borans had disconnected the power lines to Veronica's telepod with a shotgun blast, causing a shower of sparks and aborting her connection to the fusion process
• in the poignant final scene after the failed transport, anguished and completely disfigured 'Seth' flopped out of the telepod and wordlessly begged Veronica to kill his monstrous self by guiding the shotgun's muzzle to his body with a deformed claw; he wished for her to end his monstrous life with a mercy killing, although she at first begged: "No I can't"; but then she dropped to her knees after the deed was accomplished