Tonight's episode was at best I can tell, a pun on "The Invisible Man".
Episode title: Hollow Chode
Original air date: Nov. 1, 2007
Bob's intro quote: "What was Mr. Spock always looking at inside that 'viewmaster'(tm) of his?"
Summary: A fortune telling gypsy at a carnival puts a hex on Chode after he refuses to pay. The hex turns him invisible. But we soon find out that it is more than just an invisibiltiy curse that's on him.
Notes: There is a shower scene with Six in it.