Depending on the climate of your Halloween celebration, you've got the option of going full or sleeveless denim jacket since Bob is seen wearing both throughout the show. The name 'Ghost' seems to be pretty appropriate for this application, the lighter the wash the better!
Yep, you're gonna have to rock a full on 'Canadian tuxedo' to get the Bob look. Again light washes are your friend for the extra creep factor.
Finish off the look with a pair of study boots, these classic Doc's will do just the trick.