Red Shell

Target an opponent. If the opponent does not
control an untapped creature when you cast
this spell, Red Shell deals 3+X damage to that
opponent. If the opponent does control an
untapped creature, Red Shell deals 3+X damage
to target untapped creature that opponent
controls. They may tap the targeted creature to
prevent the damage, copy Red Shell and
choose a new target for the copy. X is equal
to the amount of copies made with this spell.