Pickles and Ice Cream

In an episode entitled Pickles And Ice Cream a pet belonging to Harry arrives in the Solomon's apartment one morning. He appears to have tracked him down by following his scent across several galaxies.

It isn't revealed precisely what species of animal he belongs to, as he has taken on human form along the way. His behaviour doesn't suggest anything like normal but Harry and Tommy are somehow able to pass him off; ascribing his strange behaviour to some form of psychological trauma experienced during 'the war'.

Well that explains most things. For the rest we suggest you just watch it: