First of all, I have to say that I love that spell. Cast it centered on a big bad dragon, and that dragon becomes a sitting duck for the ice staff slingers. Anyway, what I think is problematic is the fact that if a unit does not START its turn in stinking mud, it can plow through it with no problem at full movement points. Only if it begins its turn in the mud, does its speed get reduced to 1 square. The mud should prevent anyone ENTERING it from going more than one square.
