Scourge of Sanity

When Scourge of Sanity enters the battlefield, if
no mana was spent to cast it, it deals 18 damage
to each opponent.
Eternal Null (For the rest of the game, you can't
cast spells.)

What even is real anymore? Why does Magic: The Gathering exist? Why does life exist? Why is the
cardsmith having an existential crisis all over
their new card?