After exploring the lobby, you'll encounter a ghost that steals Professor E. Gadd's briefcase. Follow the ghost's trail to the garage. In the garage, you'll face your first mini-boss, a Goob. Stun it with your Strobulb, then vacuum and slam it until it's defeated. Once the ghost is gone, retrieve the briefcase and return it to Professor E. Gadd to unlock the Virtual Boo and the ability to travel between floors.
