The entry below shows most of the normal realistic skins I use in Second Life. This one is about novelty skins, imaginative creations that I can't use often but like to have on hand now and then.
The best of these is the one to the right. It's toned specifically to reflect the skin shading in black-and-white movies. Matched up with the right hair, clothes and eyes, it makes me look like I stepped out of a Bogart film ... a very cool effect.
CJ Carnot is the skin's maker, and it comes with one good set of matching eyes. It was available at Tete a Pied, but it was created as a fund-raising item for Relay For Life and is no longer there. However, the creator tells me a new version and a whole new line of skins will be available shortly.
I had put some thought toward trying to make a a skin like this myself, but I was inhibited a bit by, well, knowing absolutely nothing about making skin and also, having little in the way of artistic talent.
The one skin I have made was simply a matter of taking one of the stock SL newbie skins and coloring it for a weird alien shape I'd made. It's amusing, but hardly anything to brag about.
Possibly my next favorite novelty skin, even though it really serves no purpose but to freak people out, is the anatomical muscle skin. Bizarre Berry, who also leads the Second Life Unitarian Universalist group, made this one. What I like about it is the level of detail and also the fact that, when worn where nobody is execting such a thing, it really does freak people out.
Bizarre Berry has a few other skins available, all of them, well, bizarre. I have a couple of others but use them so rarely there's no need to picture them here. They're all available in Modesta
I have a friend in-world with a skeleton avatar (I actually have one too, but he created it.) We should work up some kind of comedy duo bit with the bones and muscles.
The Demon Skin can be used with a normal human shape, but the most effective use I've found for it is as part of the Unicorna from 6ixth. This really incredibly detailed avatar has a unicorn torso and head, but with a simple command that disappears to reveal the human torso underneath, including the skin and hair of choice. The demon, from InsideOut, is the perfect complement.
Like many newcomers to SL, it took me a little bit of time to figure out how much difference good skins make to the avatar look. As you can see from these two entries, I still don't have a big collection of them. But they really are important for anyone who doesn't want to forever look like they just stepped off of Orientation Island.