goto Jolee's house on Kashyyyk. then head south (down) on the map until you run across a wookie corpse. get the datapad off the corpse. then head south (down) somemore and you will run into the wookie you just found dead. talk to him a sec, then attack. you can get him down to within a couple VP from death then he dissappears.
then he turns into a Tach Monkey. run north (up) back to Jolee's house, then hang a right and go into the area there and start interacting with the Tach Monkeys. One will be the shapeshifer.