Back to the Pilot
In "Back to the Pilot" , two of the show's main characters , baby genius Stewie and anthropomorphic dog Brian , both voiced by series creator Seth MacFarlane , use a time machine to travel back in time to the first episode of the series , "Death Has a Shadow" . 
<triplet> Back to the Pilot <subj> Seth MacFarlane <obj> screenwriter <triplet> Stewie <subj> Seth MacFarlane <obj> creator <subj> Death Has a Shadow <obj> first appearance <triplet> Brian <subj> Seth MacFarlane <obj> creator <subj> Death Has a Shadow <obj> first appearance <triplet> Death Has a Shadow <subj> Seth MacFarlane <obj> screenwriter