As a thought experiment a Lithuanian
man designed a rollercoaster made to kill you. aptly named Euthanasia coaster. The deal is after going hella high straight up you will drop down and experience 7 loops in a row which during that time you'll get 10Gs of force and because of the loops your blood will go to the lower half of your body. Those two combined will equate to death in less than 60 secs due to lack of oxygen in the brain. for reference when the astronauts of Apollo 11 were reentering Earth they experienced 7.19 Gs
It doesn't exist in real life, just basic table models but serves as a testament to the ends of human imagination. so here's a video of someone who made it in a video game