Dreaded Thirteenth Spell

The Dreaded Thirteenth Spell has a casting value
of 8. If successfully cast, pick 1 enemy unit within
13" of the caster and visible to them, and roll 13 dice.
For each 4+ that unit suffers 1 mortal wound. You
can then summon 1 unit of CLANRATS to the
battlefield, and add it to your army. The summoned
unit can have up to 1 model for each mortal wound
that was inflicted by this spell. The summoned unit
must be set up wholly within 13" of the caster and
more than 9" from any enemy units. Th