Unlike many major movie monsters of the era which either survive or are resurrected, the titular beasts of the first Alien and Predator films are destroyed permanently at the end of their respectivedebuts. Unfortunately for mankind, those were just single specimens of entire identical races. It allows the writers to keep bringing the characters back while avoiding Joker Immunity.
The 1990s version of Godzilla dies from radioactive meltdown at the end of Godzilla vs. Destoroyah. He is not revived for another film, he's not faking it, he does NOT get better. It's one of the few films in the Godzilla franchise in which Godzilla dies and stays dead. Although his son (who was THOUGHT to be dead) takes his place at the end of the film.
Likewise, in GMK Baragon, Mothra, and King Ghidorah are all killed-off by Godzilla and stay dead throughout the rest of the film.
Also, the original 1954 film? Yes, folks, Godzilla dies thanks to the Oxygen Destroyer. Even though the original film is considered canon across all continuities of the franchise, the Godzilla that shows up in any of the sequels; he's just another Godzilla. The first one really did die. Going by Godzilla vs. Destoroyah, this also means Godzilla died for good twice.
For Your Eyes Only: The Cold Open sees this happen to Ernst Stavro Blofield. He plans to use his helicopter to send 007 to his doom; instead, the chopper's skids hook onto his wheelchair, which is then transported over to a smokestack and neatly dropped off.
No Time to Die: Due to Daniel Craig's Bond adventures being a Continuity Reboot and having a 5-film story arc, the film makers chose to end his tenure with Bond himself dying from a missile strike to protect his girlfriend and child. Yes, The Hero Dies in this one.
In Jurassic World: Fallen Kingdom, the Indoraptor is impaled on a dinosaur skeleton, and to make sure the Indoraptor can't return via cloning the DNA for its base species Indominus rex is destroyed by Rexy.
Randy Meeks: Careful. This is the moment when the supposedly-dead killer comes back to life for one last scare. [Billy starts to rise, only to receive a headshot from Sidney] Sidney Prescott: Not in my movie.
Stargate: Continuum: After dozens of Ba'al's clones have been killed throughout the last few seasons of the series and he has continually escaped death to return yet again, both the last clone and the original Ba'al are finally killed for good by SG-1.
Data in Star Trek: Nemesis. Data is revealed to have been rebuilt in Star Trek: Countdown, the canon prequel to the reboot Star Trek film, though. This was then retconned in Star Trek: Picard, where it is revealed that the download into B4 was unsuccessful. As it turns out in Picard's season 3, the three androids' memories (Data's, Lore's and B4's) are stored in the computer system of the Federation's research facility Daystrom Institute and downloaded into a void or inert Databot. After a short altercation with the oh so cunning Lore, Data's personality gets the upper hand and is resurrected for real - including Lore and B4 in one android.
While the franchise at large has killed countless characters - both with large and small roles - Terminator: Dark Fate does the unthinkable and kills the closest the series has to The Hero, John Connor, in only the first few minutes.
The original killer in the Friday the 13th series (who ISN'T Jason, but actually his mom, Pamela) dies at the end of the first movie, and stays dead throughout the rest.
Jason himself was meant to actually stay dead following his demise in Friday the 13th: The Final Chapter (hence the film's subtitle). Due to the movie's success, it was followed by another sequel Friday the 13th Part V: A New Beginning, in which Jason remains dead from the previous film. But the negative reception of this film ensured Jason's return in the following film, Friday the 13th Part VI: Jason Lives. It took until Jason X for him to finally stay down for good.
After having the distinction of being the only character who appeared in every installment of the franchise, Burt Gummer meets his end in Tremors 7: Shrieker Island when he is eaten by the Graboid Queen, saving Jimmy in the process, which then falls on some spikes and explodes when a bunch of dynamite is set off shorty afterwards.
Michael Myers from the Halloween series has a long history of cheating death. But his countless injuries finally catch up to him in Halloween Ends, where Laurie Strode kills him by slitting his throat and wrists and then placing his corpse in a car shredder with the whole town of Haddonfield witnessing the disposal.