To mistakenly merge two vast quantities of poorly organised data together (such as a porn collection), resulting in a terminally disorganised superset of data.
When you've got a big stack of porn on your computer and you accidentally copy somebody elses big stack of porn files into that directory, you've achieved cross-pornination. This is a terrible thing as you'll forever be trying to weed out your duplicates.
A "semi-dream" someone has when A) they are about to fall asleep and B)about to dream. These are fairly easy to wake up from and can be aborted at any time.