Horace Hunley, who killed himself and a bunch of others aboard a submarine he built over 150 years before the current whack job u/tuckerx78

Not killed, but the founder of Match.com, Gary Kremen, lost his girlfriend to a man that she met on Match.com. u/OneGuyJeff

Dr. Charles Drew is one of the most egregious examples. Dr. Charles Drew created/ perfected blood transfusions. He fell asleep at the wheel and lost lots of blood during the automobile accident. Since he was black, racists Jim Crow Era laws in America denied him the right to the lifesaving blood transfusion that he invented to save his life. u/Smile_Anyway_9988

Thomas Midgley Jr., a key contributor to leaded gasoline and the usage of CFC in refrigeration. After contracting Polio, he created a system of pulleys and whatnot to help him get out of bed. He was found dead at age 55 after getting tangled in his device and being strangled by it. u/heyoyo10

Jimi Heselden, Segway developer. On the morning of 26 September 2010, Heselden was riding his Segway while walking his dog near Thorp Arch; when he reversed the Segway to allow a fellow dog walker to get past him, he fell from a nearby cliff into the River Wharfe. A "rugged country version" of a Segway was found in the water. The coroner concluded that Heselden had died of "multiple blunt force injuries of the chest and spine consistent with a fall whilst riding a gyrobike." His estate, bequeathed to his widow and family, was worth over £340 million and he was ranked in the top 400 members of the Sunday Times Rich List. u/abby_normally

The French men who tried to invent a parachute and died when he decided to prove his invention was okay by jumping off the Effel Tower. u/MissFckOff

Max Valier, tried using alcohol based fuel for rockets, it blew up in his lab killing him. u/LemonsForLimeaid

Maria Skłodowska-Curie was one of the discovers of radioactivity. She discovered Polonium and Radium. As far as I know researchers did not know/believe that radioactivity might have a negative impact on their bodies and therefore they used little to no protection. u/Equivalent_Meal2688

That Indian lad who was flight testing his own, home made helicopter. Part of the rotor sliced open his head. u/peekedtoosoon

Not an inventor, exactly, but Luis Jiménez, the artist who created Blucifer, demon horse of Denver International Airport. u/corndogco

Some ancient Greek dude created a torture device called the Brazen Bull. It’s just a large metal husk shaped like a bull where you put a victim inside and heat the bottom. The burning heat and scalding metal will cause the agonized victim to go to a horn inside the husk in an attempt to breathe. The horn will make it sound like bull noises on the outside. The inventor showed a king his contraption. The king was delighted by it and decided to test it out…on the inventor. u/SatisfactionSenior65

Stockton Rush and the OceanGate submarine u/sovietslug7797979

The guy who invented the Atkins diet died from doing it. u/NDStarr

Louis Slotin - Demon Core. Accidentally started a nuclear reaction during a nuclear criticality demonstration, zapped himself with a lethal dose of radiation. u/skerries10

The guy who built the Titanic: Thomas Andrews was an Irish businessman and shipbuilder. As the naval architect in charge of the plans for the ocean liner RMS Titanic, he was travelling on board that vessel during her maiden voyage when the ship hit an iceberg on 14 April 1912. He perished along with more than 1,500 others. His body was never recovered. u/SFJetfire

Jack Parsons. Invented solid rocket fuel. And was into black magic. The rockets killed him. u/ferg286

The original Goodyear rubber guy. Died of complications likely caused by extended exposure to the chemicals he worked with to create better rubber compounds. Sad story because he also was never very successful despite his achievements and hard work. u/SHPLUMBO

Not an inventor but Carl Wilhelm Scheele was a chemist who basically discovered elements like Hydrogen, Oxygen and acids like oxalic, lactic, tartaric and hydro fluoric. The dude had a habit of tasting and touching various elements that he found like arsenic, chlorine, mercury, hydrochloric acid etc. and was killed because of it. u/Knowallofit

Otto Lilienthal, a German aviation pioneer, designed and flew various glider prototypes in the late 19th century. Despite his significant contributions to early aviation, Lilienthal died in 1896 due to injuries sustained during a glider crash. u/karimsalah97

The French king Louis XVI helped design the guillotine as a method of execution. During the French Revolution he would end up decapitated by the very machination he helped to create. u/oudeolibol