This page explains how to recruit Pip in Chrono Cross: The Radical Dreamers Edition.
Pip is a lab experiment created by Luccia.
How to Recruit
Recruiting Pip is quite straightforward. When you’re aboard the S.S. Invincible (during the ghost ship attack or otherwise), keep going until you reach the area right before the second save crystal (and the boss). You should spot a white creature–Pip–along the top of the room.
Interact with Pip and he’ll run off towards the bottom part of the room. Keep chasing after Pip until he eventually runs to the bottom-left corner. Speak to him and he’ll join your party, regardless of what you say.