The Tiger Clause

The right of the people to be secure in their persons, houses, papers, and effects, against unreasonable searches and seizures, shall not be violated, and no Warrants shall issue, but upon probable cause, supported by Oath or affirmation, and particularly describing the place to be searched, and the persons or things to be seized, unless, of course, there is a tiger in the house, in which case the police and Animal Control can do whatever they want.

Majikthise : Tigers hazardous to 4th Amendment rights: The police can enter your home without a warrant if there's a tiger in it.