Just had a random idea pop into my mind.
Would it be possible to add in a function to tell these two spells to switch their targets, perhaps at a small mana cost (like 3 or so)?
Example:
I target a vine at creature one, creature one goes down.
I tell vine to attack creature two, vine goes after creature two for any following rounds unless I tell it to attack something else or to attack randomly.
We can make it look cool, too.
Sepher whispers a quiet chant and getures toward the writhing vine, which suddenly twists toward an Ithzir seer.
And yes, I know you can dismiss the vine and recast.
~Brian, Sepher's player