The Cosmic Oscillator

The Cosmic Oscillator enters the battlefield with
three equilibrium counters on it.
Whenever you cast a spell, if its mana value is
even, put an equilibrium counter on The Cosmic Oscillator. If it is odd, remove one instead.
{1}, {t}: Draw a card. Then discard a card unless
there are three equilibrium counters on The
Cosmic Oscillator.