Azura's Star

If you control The Black Star, sacrifice it as an additional cost to cast Azura's Star.

Soul Trap — Whenever a nonlegendary
creature dies, you may tap this artifact. If you
do, you may search your library for an Enchantment with mana value less than or
equal to that creature's power and cast it
without paying its mana cost, then shuffle your library. You may not activate Soul Trap with another Soul Gem for this creature on this turn.