Buster is Zac Blakely's dog.
Buster sees Lyla spying on Zac, and barks at her. Lyla then traps Buster on a boat, and the boat drifts into a canal. Zac rescues him by using the Telekinesis power to steer the boat back to the dock. He hasn't been seen during the rest of the series, presumably locked in the house.