In no way Gizmo! Ludo could be quite annoying, going around my home saying "Smell! Smell!" and Harry would smell. E.T. would be annoyed because I have no batteries that fit his finger.. but none of them turn into a hoard of malevolent psychos at the slightest touch of water except Gizmo. And I have plumbing problems at the moment so double no. If Gizmo were here today I would have about 9000 Gizmoi and.. it's after midnight!
Edit: Oh hi Oz! I didn't recognise you for a moment. Is that a new hat?
I suppose I'd pick Mr Cool from Fonz and the Happy Days Gang? Maybe? At least he's a dog version of the Fonz. I'm not sure any of this is a good idea though. Maybe Godzuki? I had a friend I showed this to and he refused to believe it was real. I remember it and just watched it again and even now I'm not sure it's real. If I'm stuck with an 80s sidekick I may as well go full stupid!