Rose's Goatify is very "iffy"

I use Rose often, and over the time I've done so, I've noticed that when I aim Goatify at a zombie or a group of zombies, more often than not, it did not work. Sometimes when I aim at a group, I might overshoot it a bit and what would seem like half of the zombie would become goats, usually only one or two would become goats.

Not long ago, I even directly hit a zombie with a Goatify spell, and nothing happened.

I'd like to know if I'm really just that bad of a shot, or something is wrong here; if it's the latter, please PopCap, try to fix the hitboxes, or better yet, give the particle effect of the spell landing a sort of "ring" to indicate how far it reaches and who it affected.