Standard to turn into cat, full round to turn back.
Size bonus to AC and attack: +2
Size bonus to sneath: +8
+10 speed
-8 Strength
+2 Dex
Claw and bite attack
Wait an hour between changes
Lose clothes bonuses
Cannot cast spells or manipulate fine objects
Cannot activate magic items
Gain scent
Turn humanoid if killed
Spells such as polymorph show true form