It was a character from the cartoon 'The Herculoids'. There were actually two characters that looked like that, one was named Gloop and the other Gleep. Incidentally, the rhino character that fires a rock at Lois is called Tundro.
Rupert
If you mean from the episode "Emission Impossible", then it's Bertram. And he actually is born in "Sibling Rivalry" when Peter goes to get a vasectomy, decides to freeze his sperm before hand, winds up accidently destroying the other specimens in the storage room, and has to fill up every jar in order to cover his mistake. Then the two lesbian (Meg's gym teacher and her girlfriend) ask for a donor so they can have a child. 9 months later-BAM! Bertram's born to battle Stewie once again...
Bertram
September 11th
pLace
Rupert
familyguyepisodes.com
To kill Lois and the Fat Man AND take over the world
Seems like the answer is No, they don't understand him like they do the dog.
There are no named songs Chitty Chitty Death Bang.It's all music composed by Walter Murphy.
There is an episode, "Family Goy" where Peter tears apart Stewies crib and uses the pieces to make a giant cross for Lois.
He doesn't have one. He does however have a younger half-brother named Bertram, at least "younger" in the respects he was born after Stewie but in his 2 appearances after he was born he appeared the same size and age.
Because the original Peanut Butter Jelly song featured an animated dancing Banana image.
Eric Cartman because stewies cute and swears a lot and too much gun shooting makes him hyper