Toyota engines...

[1clearshot]

Nobody is immune to lack of maintenance.

About 70% of'em made past 300k miles with a dozen or so in 500k +

 

[1clearshot]

What not to do when the engine is overheating.
Continue driving until extreme heat drops the seat out of the head.

No clue as to how this happened.
My only speculation is the engine overheard the driver saying how he's ok with some gun control laws for safety of children and greater good.
Then it decided to commit seppuku.