the-valley
Explanation
A guide welcomes a visitor to "The Valley of the Unicorns," explaining that the unicorns can only be seen because the visitor is a virgin. The visitor, rather than being flattered, asks "Can they see me?" The guide responds "Not even close," delivering the punchline.
The joke subverts the classic mythological trope that unicorns are attracted to virgins or can only be perceived by the pure. Here, the unicorns themselves apparently have standards -- they cannot or will not perceive the visitor, implying the visitor is so far from meeting whatever criteria the unicorns look for that it is not even worth considering. A secondary reading, reinforced by the guide's additional comment "No, the unicorns are not virgins," adds another layer: the magical purity requirement is a one-way street, and the unicorns themselves do not meet the standard they demand of humans.
The comic plays on the absurdity of mythological purity tests and inverts the power dynamic of the "only virgins can see unicorns" trope.