Last night Disney Parks dropped a bomb and revealed that the rumors are true - the Tower of Terror at Disney California Adventure will be replaced with Guardians of the Galaxy - Mission: Breakout! in mid-2017. The last rides on Tower of Terror will take place in early January of 2017.
For months there has been talk around the interwebs that Disney was looking at bringing in the powerhouse Guardians franchise to the west coast, with much of the talk centered around an overlay of the Tower of Terror. When complete the famous hotel will have scattered all of its ghosts and will look like this:
Joe Rhode is in charge of the project, and is dropping hints that plenty more Marvel related attractions will eventually spring up in the Hollywood section of California Adventure. He gives a lot more description about the new attraction in the below video.
The summer opening of the ride will tie in perfectly to the second Guardians of the Galaxy film, which will open just before it. And to be perfectly clear, this change only applies to the California version of the ride, not the original Tower of Terror in Florida.