I can't remember the name of some 90s kid/teenage show. The beginning of the show starts with good aliens coming down to earth in a space ship and giving some kids powers to turn into animals, so that they can fight some bad aliens. The bad aliens are on earth, and possess people. They're sluglike creatures. People get possessed when an alien puts a slug in their ear. In one episode a kid got a cell phone with a slug in it. One of the main characters whose a blonde girl also loses her memory and almost gets a slug put in her ear, but gets rescued by one of her friends who turns into some large cat... probably a tiger.