Twin films are films with the same, or very similar, plot produced or released at the same time by two different film studios. The phenomenon can result from two or more production companies investing in similar scripts around the same time, resulting in a race to distribute the films to audiences. Some attribute twin films to industrial espionage, the movement of staff between studios, or that the same screenplays are sent to several film studios before being accepted. Another possible explanation is if the films deal with topical issues, such as volcanic eruptions, reality television, terrorist attacks or significant anniversaries, resulting in multiple discovery of the concept.