As you prepare to leave, though you are wracked by another round of aches and cramps, and your ears start to grow tall and hairy as they slip through slits in the hood/mask. At the same time, you feel a pressure at the base of your spine, and you feel a long ropy tail emerge from a slit with a similar purpose in the back of your gi. You cry out in a voice which has grown strangely coarse and raspy as your nose and mouth push out into a muzzle and your feet cramp and stretch into hooves.
Finally, the changes are complete, and you let out a sigh that sounds more like a soft bray. You are now really a badass ninja.