all animals use skin. without any skin, we couldn't mate, let alone live.
courtship
courtship
dolphin
the worm especially earthworms
Echinoderms
Echinoderms
There is no single answer to this question, an organism may use luminescence to attract a mate, attract prey, distract predators, or other uses.
The animal skin in "Island of the Blue Dolphins" is called otter skin. Karana, the main character in the book, uses otter skins to create clothing and other items for survival on the island.
The mouthpart of the male Anopheles mosquito has sharp razors that are used to lacerate the skin of an animal. The mosquito then uses the sucker to extract blood.
Anyone can give a 2 minute speech on animal cruelty. The speech could be about the uses of fur, animal testing, and the poaching of animals for their meat, skin, and fur.
She uses the complete package of ProActiv. It's expensive and very effective on skin that removes zits and makes skin clear.
I think what you are referring to is Henna Tattooing, which uses a kind of ink that stains the skin for a short period of time (about two weeks.)