A ninja cooter is a rare and magical creature that finds itself on the edge of sexual situations frequently, but due to being cloaked in the shadows is never quite capable of ‘sealing the deal’ with qualified supplicants, as it were.
When aroused it has a haunting presence that draws human males for miles around, but when they get within ten feet of it, it disappears entirely, causing much frustration and gnashing of teeth on both sides.
Sometimes, when the moon is full and the fates are kind, the ninja cooter is able to track a target and successfully bring it to ground, but the resulting damage from the frantic and violent coupling that follows takes months for it to recover.
It’s been said that the natural tendency to cloak in these situations is a defense mechanism. The owners of said ninja cooters call bullshit on this, but the universe has chosen to damn the ninja cooter to a life of furtive frustration and angst.