It is possible in some people that over-oxygenation will cause the brain to shut off breathing, leading to death.
In most people the brain monitors the CO2 level in the blood. Increased CO2 increases acidity, and the brain stimulates breathing to reduce CO2 levels. In some people this mechanism does not work - the brain monitors O2 level instead. Pushing up the O2 level over more than a brief period can cause the brain to slow down or suppress breathing.
A normal healthy adult should have a blood O2 saturation ("sats") of around 96 to 98%. 100% is abnormal. Elderly adults can have sats in the low 90's and still be ok. Persons with COPD, long term heavy smokers and possibly others, may have sats around 88-92%, which for them is normal.
Each person has their own sats level of "normal". Driving it too high can be dangerous. It can also cause tissue damage. Over oxygenation can cause constriction of heart arteries - bad news for anyone with a pre-existing heart condition, whether they are aware of it or not. I suspect most of us on this forum come under "elderly", in body if not in spirit. I strongly recommend discussing it with your doctor before trying out experiments like the above.