In the episode Lights Out!, Hector is skateboarding by himself, without a helmet on, and falls down stairs and receives a concussion. Inside his body, nobody remembers Ozzy and Drix because they were the most recent arrivals inside Hector, so it is up to Ozzy and Drix to find the location of the concussion. In the end, Ozzy and Drix save the day and everyone remembers them again. Travis finds Hector in the park and helps him home.
This is a very informative episode. It teaches kids the importance of helmets and what could happen to you if you neglect to wear them. It shows that you always need to think one step ahead to insure your safety, because, as shown in this episode, if Hector had done that and worn his helmet, it would have saved him from experiencing a concussion.