Disney California Adventure has announced a Halloween Overlay for its newest attraction:

Quote Originally Posted by Disney Parks & Resorts
Your adventure picks up moments after the events of the popular Guardians of the Galaxy – Mission: BREAKOUT! attraction. The Guardians have successfully escaped The Collector’s Fortress, but they have accidentally left Groot behind! Rocket enlists you to distract the creatures that have been released so he can find and rescue his little buddy. While The Collector’s ever-resourceful assistant, Apheta, may try to assure you that it is all just a momentary setback, we advise you to proceed with caution!

Once the sun sets each evening during Halloween Time at the Disneyland Resort, Guardians of the Galaxy – Mission: BREAKOUT! will transform into Guardians of the Galaxy – Monsters After Dark. Music continues to be at the heart of the experience, and an all-new song, “Monsters After Dark,” was created especially for this attraction by Tyler Bates, composer of the “Guardians of the Galaxy” films.
The Monster After Dark version of the attraction will operate during Halloween Time, September 15-October 31, 2017.