Bit of an unusual medium here... this is UV acrylic paint, airbrushed onto skin (a friend's back, in this case). A bunch of people I know are into bodypainting, so every so often we get together and have painting parties, usually with blacklight paint (in a darkened room full of blacklights, of course). It's a lot of fun.

This particular subject asked me to put tentacles on him, and so I did. :D

Unfortunately this kind of art really is better viewed in person, under actual ultraviolet light... but it's also temporary, as it gets washed off at the end of the night. So a photo will have to do. This one turned out reasonably well, I think.