RedactedNarrative: Vessel 1 was following Vessel 2 Southbound in Perdido Pass.  Vessel 2 had stopped to do a mock attack on a passing dolphin cruise with water cannons.  Vessel 1 was coming up behind Vessel 2 and did not notice they had stopped.  Vessel 1 had to attempt evasive magnifiers in an attempt to avoid contact with Vessel 2.  Vessel 1 was unable to avoid Vessel 2 and struck the rear starboard of Vessel 2.  The operator of Vessel 1 stated he thought Vessel 2 was backing up at the time.  The operator of Vessel 2 stated he was sitting still at the time of the crash.  None of the occupants on either vessel were injured.