Brendon Bennetts is haunted by ECTO-1 (Jeff Clark and Karen Healey), The Mystery Machine (Matt Powell and Grain of Truth host David Innes), and Cusdin the Friendly Ghost.
(Sorry this episode is up late: Matt vanished and nobody else could solve the mystery of how to upload the file. Turns out Old Man Withers stole the password. Also sorry about the previously-missing final 17 minutes or so of this episode. Hopefully everything is fixed now.)