TVGuide.com: Tell me about this very "different" episode
Bones has planned for before the season finale. We've got Patricia Belcher and Ryan O'Neal returning (as Caroline Julian and Bones' father), Eric Millegan is back as Zack, and we've got... "Stewie" from
Family Guy. Um, have you seen the script for this?
Taylor: No one has seen the script yet, they've kept it really quiet. I know that it's... how do I say this without blowing anything... hmmm ... it's a sort of "altered reality" episode.
Source: TVGuide