What is this box?

So I was driving around on my motorcycle just now and I've come across this burried box in the middle of a lake.  What is it, does it have a purpose? It has not solid surface, just flashes purple and yellow with quuestion marks all over it..View attachment Ee5diY-WoAEaWka.jfif

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[n2n1]

This block is called the "missing block".

It means that this block no longer exists. Maybe it's because of the mod or the old world of the game.