A crab infestation so horrific that it may be possible for the crabs to spread without sexual contact, since clothing can not contain them. It is as if the crabs have the ability to phase through the infected person's clothing and that of others, thus attempting to use their ghostly powers to reach a pandemic state.
Brooke: "Mike is so hot! Too bad that he has ghost crabs."
Alison: "I know, yesterday I had lunch with him and had to shave my junk as soon as I got home."