If it exists, there is porn of it. If there isn't, there will be.

Only one known exception: rule 34 itself.

there is porn of everything somewhere.

/ryool-thər'-tee-fohr/ n., pl. Rules 34 - The 34th rule of the Internet, which states that any object, character, or media franchise imaginable has porn associated with it. The only exception to this rule is outlined in Rule 35.

v., p.t. Rule 34'd - To make an object, character, or media franchise comply with Rule 34.

Generally accepted internet rule that states that pornography or sexually related material exists for any conceivable subject.

Additionally it is accepted that the rule itself has limitations and you cannot be too specific on the content of the item in question.

Most commonly used on various message boards for various reasons, from humor to cruelty.

If it exists, there is porn of it.

There is porn of it, no exceptions. It is an internet based "rule" derived from a set of generalizations about things you will find on the internet, this one basically referring to how no movie, show, books, or especially children's cartoon is safe from having porn drawn of its characters. It is usually accompanied by people who claim viewing it has "raped their childhoods."
If there is no porn of it, which is of course impossible, it invokes rule35: if there is no porn of it, porn will be made.

Rule 34: If it exists, there is porn of it. No exceptions.