There was a boy and a girl, and they had a small puppet creature with the name of Prism, and at the end it turned into an actual prism of crystal on a necklace, I think. Near the end, it might be that their ship was being eaten by multiplying slug puppets?
From a review on IMDB:
Storyline is definitely for juveniles: Josh encounters time traveling pod and its occupants (Irwin, Azebeth & Prism) and is pursued by Dr. Zoetrope who is trying to obtain the crystal pieces of a time nullifier device. At least the ending (in episode 6) has a twist. Azabeth is a headstrong girl who eventually likes Josh. Prism is a cute little alien who reminds me of a cross between gremlins & yoda. Irwin is the professor running the time pod trying to get the nullifier pieces before Zoetrope can. Each episode leads into the next just like old time serials did.
In the sixth episode, Josh meets a girl with the prism on her necklace (played by a young Charisma Carpenter!). The slug puppets is probably from the fourth episode, "Time Warrior- Eggs From 70 Million B.C."