Many Puppet Up! shows are opened by Mr. Guy (performed by Brian Henson) and his dog Piddles (performed by Julianne Buescher). The frantic Mr. Guy welcomes the crowd to the show and explains the show, or rather shows, that the audience is about to see -- the puppet show on the monitors and the chaos happening below. He tells the viewers to ignore any heads or extra arms that might show up in frame (as everything is live and unrehearsed), while simultaneously trying to keep Piddles from mingling with the puppeteers below.
The puppet has been used in various roles and by various performers depending on the sketch. The puppet has also appeared on occasion as a newcaster performed by Drew Massey, adopting such names as Dick Hardschmedley or Hank Schmuckley.
Mr. Guy's puppet has appeared in Alt/Reality in different roles, in the Neil's Puppet Dreams episode "To Catch a Puppeteer" as Puppet Chris Hanson, and in That Puppet Game Show as Jake Hamilton-Jones.
The puppet was designed by Drew Massey for Puppet Up!.