elaby - I can't figure out WHERE they come from O.o
caitirin - you see... when a plot bunny and your subconscious love each other very much and they want to express that love in a special way... They screw each other into the floor and you get bizarre dreams ^_^
hak42 - I'm picturing little animated screws with arms and faces, one of them has bunny ears. One of them takes a giant screwdriver and reach over and screws the other into a wooden floor, then the other one reaches up and takes the screwdriver to screw in the first.
From this post.