"You'll have to excuse Frederic... he hasn't been the same after... well, you remember."
-Subrhone Malfes Sternbrugge, Custodian of Prince Fredric van Heinhelm.
"If the OD-RSDs were here already, the facility would have gone up in smoke a long time ago..."
"This is Skybase Alpha-One broadcasting to Skybase Alpha-Two through Six. Seventeen point zero VD-TD Drop Ships inbound towards Korolis Sector, Quadrant Two. ETA approximate - 0030 hours. Recalibrating Ground Ordinance to avoid excess Friendly Fire. Reaffirming aerial perimeters and air supremacy..."
If a creature is transformed into another creature (say, a human into a dog), then that creature will become more and more accustomed to the new form until a point is reached where reversing the spell is impossible. A second transformation is possible, but the creature will have to go through the whole process again.