No backstory exists for Clover, all that is known is that it was a 350 foot monster that lived in the ocean and was awakened by a falling satellite dish. The protagonists of the film were unfortunate to have encountered the monster's attacks four times. Clover rampaged through New York and killed any human it came across, worse a number of giant parasites were released from its body and attacked the humans as well. It even went as far as to rip the head off the Statue of Liberty and toss it into New York.