"It's" is a magic word which summons the show.The "It's" man always seems to be in a state of either complete exhaustion, mortal peril or both. When he's at the end of his rope, his ace up his sleeve is saying "it's", which instantly cues half an hour of total nonsense during which he can catch his breath and/or try to think. It rarely seems to help, however. The only person immune to his powers is The Colonel, who always notices and points out that things have gotten awfully silly.
The Dead Parrot Sketch was inspired by Richard Wagner's opera The Flying Dutchman.The opera begins with the Norwegian sailors singing about how they're pining for the fjords of their homeland; Monty Python replaced the Norwegian sailors with a Norwegian parrot. Like the Dutchman, who is doomed to wander the earth forever, Mr. Praline is doomed to wander between Ipswitch and Bolton seeking a replacement. And just as the Norwegians (especially the helmsman) seem almost comically unaware that anything is wrong when the Dutchman shows up, the pet shop owner refuses to believe anything's wrong when Mr. Praline arrives with the dead parrot.