(ignoring my obvious scars from cancer surgery) this might be amusing
When I was about 13 I decided I wanted some Sodium metal (it's dangerous in its own right) so thought a clever idea would be to melt some caustic soda in a crucible and electrolyse it. All this in my bedroom just before tea time, no safety glasses or other gear. Alcohol burner set on full and a whole 9 volts applied it was going nowhere when suddenly the call comes "get down here now your tea's ready" Alcohol burner off PDQ but clearly there was this molten mass to make safe.
In perhaps the dumbest thing a 13 year old could do I decided to add water to it. It exploded and yet somehow it all missed me apart from one small piece of molten caustic soda that landed on my right hand. Jeez did it fucking hurt as it burnt a thermal and chemical hole right down and eventually a small white scar resulted. Used to look at it every so often as a 'do not be a moron again' reminder
But here's the thing: went looking for it about 50 years later and it's gone
Now I can be a moron again