A crush fetish is a fetish in which one is sexually aroused usually when someone crushes objects, food, and sometimes small animals (frequently insects) with their body, usually under their foot, or when crushed oneself. The term soft crush refers to the more common fetish surrounding videos involving inanimate objects (such as food) or small invertebrates (e.g. insects, snails, worms, arachnids) being crushed, while the term hard crush refers to such videos involving larger animals with vertabrae, and arguably more pain-susceptible animals (e.g. reptiles, birds, mammals).  The preference could be barefoot, high-heels, flip flops, and so on, depending on the fetishist.
Crush fetishes typically form between childhood and adolescence. The main reason that crush fetishes form is that the child/adolescent who acquired it, experienced a situation in which they deemed shocking or had an impact on their life while experiencing puberty. The brain performs a mental substitution for the person forming the fetish and links it to sexual stimulation. Later on, when a similar experience is performed, the neurotransmitter Phenethylamine (chemical responsible for infatuation and love) is activated and provokes sexual arousal. Continued thoughts and exposure to such scenarios strengthens the connection increasing the likelihood of it becoming permanent. 
Most soft crush fetishists avoid being placed under the same label as hard crush fetishists, believing that crush films with larger animals give the entire group a bad label. "It's like associating every Christian with the zealots who cause religious wars. Not all crush fetishists are that extreme!"  There are currently no known laws forbidding the crushing of objects and insects, however the production or trade of crush erotica involving live vertebrates is condemned by animal rights activists and is illegal in many countries, including the United States and Great Britain.  In the United States, creating, distributing, or possessing [hard] crush videos has been illegal since 1999, and many other countries also have banned them. 
Jeff Vilencia is one known director of crush films, such as Smush! Vilencia, along with many other fetishists, has loved to see invertebrates crushed since a young age; he claims that when he was 2–3 years old, he repeatedly attempted to get people to step on him.
The legality of crush films and the actual practice of crushing varies by region, however, many have been posted on web sites and are available for download via the Internet, making the control of their distribution difficult.
There are currently no known laws forbidding the crushing of live invertebrates, although the production or trade of crush erotica involving vertebrates is condemned by opponents of animal cruelty and is illegal in many countries including the United States.
In 1999, the United States Congress enacted a statute affecting the legality of crush films which criminalized the creation, sale, and possession of depictions of animal cruelty, though with an exception for "any depiction that has serious religious, political, scientific, educational, journalistic, historical, or artistic value." In 2008, the United States Court of Appeals for the Third Circuit invalidated the ban on the sale and possession of such films (if not otherwise obscene) as a violation of the Constitution's guarantee for freedom of speech. The United States Supreme Court affirmed the Third Circuit's decision in United States v. Stevens, finding the law unconstitutional because the law was so broad and vague that it included any portrayal of an animal in or being harmed such as by hunting or disease. As of November 28, 2010, bill H.R. 5566, which prohibits interstate commerce in animal crush films, has been passed by the House of Representatives and the Senate, and as of December 9th, the bill has been signed by President Obama.
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- Dr. Mark Griffiths, (May 17, 2012). A Beginner's Guide To Crush Fetishism
- 2014. How Do Crush Fetishes Form? 
- Thoswal. (March 2014). Hear A Crush Fetishist Out
- Crush Films
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- § 48. Depiction of animal cruelty. United States Code: Title 18, Part I, Chapter 3, § 48. Cornell University Law School
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- Adam Liptak (April 20, 2010), Justices Reject Ban on Videos of Animal Cruelty, New York Times
- H.R. 5566: Animal Crush Video Prohibition Act of 2010. www.govtrack.us