Parasitic Biomage

When Parasitic Biomage enters the battlefield,
discard a creature card with mana value lower
than this creature's mana value: Put X -1/-1
counters on target creature and X +1/+1 on
this card, where X is the discarded creature's
mana value.
Madness {1}{g/u} (If you discard this card,
you may cast it for its madness cost instead
of putting it into your graveyard.)