[These are] promotional masks that were issued [by Lyausa] to promote the [card] set. Among trading card collectors, it is currently unknown exactly how they were distributed. These images come from collector Scott Gaynor, but I do not have his contact info. Sorry, don't have a back image for the Human mask. There has been some discussion that there might have been 3 masks in the set, but all I've ever seen are the below two.