Warner Bros. has made a lot of money off of Christopher Nolan. The fan-favorite director has made five films for the studio, which combined have made a staggering $3.5 billion at the global box office. So, it's only logical the studio intends to stay in the Christopher Nolan business, which is probably why its bean counters had a heart attack when it just so happened that Interstellar, the next project he was interested in, was already owned by Paramount.
Unwilling to let Paramount have Nolan's 2014 sci-fi movie starring Matthew McConaughey to themselves, however, the people at Warner Bros. had to make a few concessions to get on board. The studio shared the rights to two very popular franchises with Paramount, and its Interstellar deal meant that it had to relinquish its ownership of those entirely to Paramount. The franchises? Friday the 13th and South Park.
The Hollywood Reporter has the details of the deal, which helps explain why we never got a sequel to 2009's Friday the 13th. The film certainly did well enough to deserve one ($91 million off a $19 million budget), but apparently the two studios could never agree on where to go with the next one, so it never got off the ground. This paves the way for Paramount to do one itself, should it want to.
This doesn't mean that Friday the 13th and South Park movies are right around the corner; it just means Paramount can make them without having to clear everything with another studio first. However, Warner Bros. is only relinquishing these rights for five years, so, if Paramount is going to move on either one, it needs to soon.