Nox, Katronova's Guardian

Whenever you discard a card, you get an
experience counter.
Whenever an opponent(s) casts a noncreature
spell, create a 2/2 colorless artifact scarecrow
creature token with "{t}, Discard a card: Target
permanent gains indestructible this turn."
Nox, Katronova's Guardian's power is equal to
the number of experience counters you have.