Hey @Gemgirl and @Lolalovelocs,
We believe that the Spooky Imp has the same issue as the Baby Dragon with the Transform part of his spell. This should only be occurring in Quest, Explore and Challenge battles, but should not affect using Spooky Imp in PvP.
As ColonielZoland88 mentioned, unfortunately all Transform spells currently break the game when used on the opponent team outside of PvP or Arena. This will be fixed in the next version.