Described herein are semi-permanent tattoo transfer devices or structures for applying semi-permanent tattoo images to the
skin of human and animal subjects, and image-forming compositions used in the devices. The devices are used to apply a flexible image-forming composition layer to an human or
animal subject's
skin, wherein the image-forming composition layer is comfortable for the subject to wear and will eventually slough off with
normal skin cell turnover of the subject's
skin. Within about 24-36 hours after application to the subject's skin, an image-forming component (such as
Genipin) in the image-forming composition layer causes development of a tattoo image on the skin, due to interactions with the skin or components of the skin. The devices may also be used to apply an image-forming composition that dyes the skin (such as Henna) instead of reacting with the skin to color it as does
Genipin. Use of the devices results in the formation of a semi-permanent tattoo image on the subject's skin, wherein the tattoo image lasts for one to two weeks and is semi-permanent, meaning that the tattoo image cannot be removed by washing or even scrubbing the subject's skin.