Wrecking Ball

Convoke (Each creature you tap while playing this spell reduces its cost by {1} or by one mana
of that creature's color)
1-5= Destroy target creature or nonbasic land.
6-10= Same as above except you may do both.
11-15= Same as above except you'll shuffle this
back into your library after the spell resolves.
16-20= Same as above except it {1} less to cast.