My dog, as you know, is named Lemmy. His middlename is Hairy-Balls, and i registered him at the vets under that name. Once a year I receive a letter addressed to the owner of Lemmy Hairy-Balls Farquhar, which always gives my a childish fit of the giggles.
I have 2 cats. Tibbles was already named when i got her, so no hassle there.
My other cat, a female, was un-named when we got her. After much arguing in the family we agreed to name her after the first female we saw when we switched on the TV. The first female was Lois Griffin, so Lois it was. However, when i registered her at the vets I had one of those moments where Lucifer takes me over, and as I filled out the form I wrote "s***-for-brains" as her middle name. I now received a second periodic letter, and have a good titter.
My father in laws dog is called Tess. I convinced my then 7 year old niece that Tess' middle name was Tickles. One day she was walking the dog and calling out "Tess Tickles, Tess Tickles!!!" Unfortunately, her dad, my BiL, us a chump and didn't see the funny side and had a right moan at me. To get my revenge I then taught my niece to speak French, which involves speaking in English with a funny accent and going haw-he-haw periodically.
There's a spaniel down our street called Daniel.
There's a Beagle further along the village named Benson, and in Benson and Hedges, which I like.
My oldest daughters enormous Rottweiler is called Bully, which is a name granted in irony as he's the gentlest, most cowardly thing you'll ever meet.
And I know of a German Shepherd called Kaiser, after Kaiser Willhelm.
A friend of mine has a cat named budgie.